Perciform fishes (phylum Chordata, subphylum Vertebrata, superclass Osteichthyes, class Actinopterygii, order Perciformes) are mostly fishes with dorsal fins that are hard and spiny in the front portion, but soft towards the rear. In some species, these two portions are split into two separate fins: the spiny dorsal fin and the soft dorsal fin.
Being ray-finned fishes, they are characterised by their fins being supported by rays of bony/horny structures, much like those paper folding fans supported by rays of sticks. Most species have a layer of scales covering their bodies, while some may have very reduced scales or no scales at all.
Here are some examples of marine perciform fishes that can be seen in Singapore.
Family Apogonidae
Members of this family, commonly called cardinalfishes, have two separate dorsal fins. They usually have ovate to elongate bodies, relatively big eyes, and a protruding lower jaw. While the colour may be quite variable, many species have dark bars or stripes on their body. They are mouthbrooders, with the males holding the eggs in their mouths. Most species are nocturnal, feeding on zooplankton and small invertebrates.
The Candystripe Cardinalfish (Apogon endekataenia) can usually be identified by the black spot on its tail, and the many thin horizontal stripes on its translucent body. It grows to about 10cm long.
The Checkered Cardinalfish (Apogon margaritophorus) has several broad, brownish to reddish horizontal bands on its body, and the band in the middle is broken by a series of pale spots, giving it an "airplane window" appearance. This species grows to about 5.5cm long.
Family Blenniidae
The true blennies are usually elongate, scaleless fishes with long dorsal and anal fins with flexible spines. They are usually bottom-dwellers, and hence the eyes are usually high up on the sides of the head to give them a good view of the surrounding. Most species feed on small invertebrates.
The Variable Fangblenny (Petroscirtes variabilis) has a pair of long curved fangs on its lower jaw. It is olive above and greenish-yellow below, with several large irregular dark blotches along the upper side. It gets to about 15cm long.
The Yellow Tail Black Blenny (Enchelyurus flavipes) is largely black with a yellowish tail. It gets to about 6cm long.
The Light's Rockskipper (Entomacrodus lighti) grows to about 11cm long, and can be recognised by the series of dark vertical bars along its body and reticulate pattern on its head.
The Striped Poison-fang Blenny (Meiacanthus grammistes) is a venomous blenny that can be recognised by the yellowish head and black horizontal stripes which are broken into spots towards the tail. This species grows to about 10cm long.
Family Callionymidae
Commonly called dragonets, members of this family tend to have elongate and moderately compressed bodies. The eyes are on the dorsal side of the head, since they are mostly bottom dwellers and this will allow them to have a good view of the surrounding. They have protrusible upper jaws, feeding mostly on small invertebrates.
The Mangrove Dragonet (Callionymus enneactis) is the only species known to be associated with muddy substrates, though it can be seen on sandy areas as well. It is can be recognised by having a narrow snout, dark saddles on the body, and dark markings on the anal fin. This species grows to about 8cm long.
The Smallhead Dragonet (Callionymus erythraeus) has a wavy line separating the patterns on its back, and dark markings on the anal fin. It can be differentiated from similar-looking species by the lack of a distinct dark spot at the base of the pectoral fin and anal - fin rays. This species grows to about 10cm long.
Family Chaetodontidae
Members of this family are commonly called butterflyfishes, as most species have eye-like spots and interesting patterns on their body, much like those on the wings of butterflies. They have small mouths located at the tip of a snout (which can be long or short depending on the species). The body is highly compressed. The eye-like spot serves to confuse predators as it resembles a fish facing the opposite direction. A predator which attacks the false "head" will only end up getting part of the tail fins.
The Copperband Butterflyfish (Chelmon rostratus) can be easily identified by the broad orange bands on the sides, the big black spot on the dorsal fin, and the long snout. It can grow to about 20cm long, feeding mostly on worms.
The Kite Butterflyfish (Parachaetodon ocellatus) has four brownish bars on the sides and a black spot the dorsal fin. It has a short snout, and feeds on sea anemones, coral polyps and sometimes, small invertebrates. This species can grow to about 18cm long.
The Eight-banded Butterflyfish (Chaetodon octofasciatus) has a short snout and about 8 narrow black bands on the sides. This species grows to about 12cm long. It feeds mostly on coral polyps. The above photo was taken in Malaysia.
Family Drepaneidae
Members of this family, commonly referred to as sicklefishes, are highly compressed laterally and somewhat disc-shaped. The spiny portion of the dorsal fin is separated from the softer portion by a deep notch. They have small, protractile mouths, feeding on small invertebrates.
The Spotted Sicklefish (Drepane punctata) and the Barred Sickelfish (Drepane longimana) have similar shapes and can only be differentiated by the patterns on their body. The former has numerous vertical rows of black spots, while the latter has numerous dark vertical bars. The above picture, unfortunately, features a sleeping sicklefish which has turned all black and hence it is not possible to tell the species. They are mostly found in coastal waters, growing to about 50cm long.
Family Echeneidae
Members of this family, commonly called remoras, have elongate bodies and flattened heads bearing sucking discs. These sucking discs allow them to attach to larger animals such as marine mammals, turtles and other fishes, effectively reducing the amount of energy used for moving around.
The Slender Shark-sucker (Echeneis naucrates) has an oval sucking disc on its head. While they are perfectly capable of swimming on their own, they are often seen attached to sharks, turtles and even ships. This species can grow to about 1m long, and feeds on small fishes, bits of its host's prey or the host's parasites.
Family Ephippidae
Members of this family are commonly called spadefishes as they are laterally compressed and appear somewhat spade-shaped. They are usually silvery or grey with darker bars or spots. The juveniles and the adults tend to have very different appearances. They mostly feed on seaweed and small invertebrates.
The Round-faced Batfish (Platax teira) has juveniles (see above) with very long dorsal and pelvic fins, but they eventually shorten as they mature (see photo of an adult taken in Malaysia). The adult is usually silvery or greyish with a convex lateral head profile. There is a dark vertical band running over the eye, and another just behind the gill cover. This species can grow to over 60cm long.
Family Gerreidae
Members of this family, commonly called the mojarras, have laterally compressed bodies that are usually silvery in colour. They have protrusible jaws, and the tail fin is usually forked. Most species live in large schools, though some species may live in small shoals or alone. They usually feed on small invertebrates which they grab from the seabed together with the sand, after which they will expel the unwanted sand and debris.
The above is a Silver-biddy (Gerres sp.) with silvery scales and yellowish fins.
Family Gobiidae
Members of this family, commonly called gobies, have short and broad heads, usually with the eyes located either on top of the head or high up on the sides. They are mostly bottom dwellers, and hence the higher location of the eyes allows them to have a good view of the surrounding. Many species can survive well in both brackish and sea water, while some may spend their entire lives in freshwater. Several species form symbiotic relationships and live with other organisms, such as shrimps, corals and other fishes - they aid in the detection of threats, remove parasites, or protect their hosts from predators. Some species, e.g. the mudskippers, can survive for long periods out of water by holding water in their gill chambers and/or breathing through the skin. During the breeding season, the males will usually guard and tend to the eggs.
As this is a rather large family, I have decided to provide more details and highlight the gobies I have photographed in another blog entry: Mudskippers & Other Marine Gobies (Phylum Chordata: Family Gobiidae) of Singapore.
Family Haemulidae
Members of this family are commonly referred to as grunts, due to their ability to produce a sound by grinding their teeth. The first half of their dorsal fins usually have strong spines. Many species have obvious, thick lips. They mostly feed on small fishes or invertebrates. A number of species are important food fishes.
The Brown Sweetlips (Plectorhinchus gibbosus) is usually brown, dark grey or black in colour. It has obvious thick lips and rounded tail fin. This species can grow to about 70cm long.
Family Labridae
Members of this family, commonly called wrasses, have protrusible mouths, obvious lips, strong jaws, and a single, long-based dorsal fin (in most species). They have very diverse feeding habits, and depending on the species, may feed on algae, plankton, and a variety of small animals.
The Green Pastel Wrasse (Halichoeres chloropterus) can often be recognised by the light green to yellowish body with intricate reticulate pattern of bands on its head. Some specimens may have a large dark blotch on the sides. This species grows to about 19cm long, feeding mostly on hard-shelled prey such as crustaceans, molluscs and sea urchins.
The Diamond Tuskfish (Halichoeres dussumieri) can be recognised by the dark and broad bars on the side, a dark spot on the middle of the front half of the dorsal fin, and another at the base of the pectoral fin. This species can get to about 16cm long.
Family Lethrinidae
Commonly called emperors, members of this family often have soft, obvious lips, a protrusible upper jaw, and molar-like or conical teeth for crushing their prey. Many feed on shelled animals such as crustaceans and molluscs, though some may feed on other fishes and invertebrates.
The Spangled Emperor (Lethrinus nebulosus) can usually be recognised by a few blue streaks radiating forward from the eye. The body color is yellowish or bronze, many of its scales have a whitish or pale blue spot in the middle. This species can grow to over 85cm long.
Family Monodactylidae
Members of this family are commonly called moonies for the round, strongly compressed body and silvery colour. Most species have prominently protruding dorsal and anal fins. They usually occur in schools in coastal areas, such as estuaries and shallow coral reefs, sometimes venturing into brackish and even fresh waters. Most feeds on plankton and detritus.
The Silver Moony (Monodactylus argenteus) is the only member of its family known to occur in Singapore waters. It has a silvery, somewhat disc-shaped body with protruding, yellowish dorsal and anal fins. It usually has a black vertical stripe on its head, running over the eye, and another over the gill cover. This species gets to about 25cm long. The above photo was taken in Malaysia.
Family Mullidae
Mullid fishes are commonly referred to as goatfishes due to the two long barbels on the chin. They generally have elongate bodies and a relatively big head. They usually inhabit shallow waters, and are often seen hunting at the bottom, using their barbels as chemical receptors to detect small animals hiding in the soft substrate. When a prey is located, the goatfish will poke its snout into the substrate to catch it.
The Freckled Goatfish (Upeneus tragula) can be recognised by a pair of barbels under the chin, dark stripes on the dorsal fins and tail fin, and a dark stripe along the side of the body from the snout to the base of the tail. This species reaches lengths of about 30cm, and is often used for human consumption. The above photo was taken in Malaysia.
Family Plesiopidae
Members of this family typically have elongate to oblong bodies with long fins, and hence they are also commonly called longfins. They are usually seen in coral reefs, feeding on crustaceans and molluscs.
The Comet (Calloplesiops altivelis) is a popular aquarium fish, and has been successfully bred in captivity. It can be recongised by its oblong shape, the numerous white spots, and the presence of an eye-like spot near the middle of its back. The eye-like spot serves to confuse predators as it resembles a fish facing the opposite direction. A predator which attacks the false "head" will only end up getting part of the tail fins. This species has also been observed to insert its head into a crevice when alarmed, exposing only its backend to mimic the head of a moray eel. This species can grow to about 20cm long. The above was an aquarium shot.
Family Pomacanthidae
This family comprises the marine angelfishes, which generally have highly compressed bodies. The dorsal and anal fins extend towards the backend, giving them an overall spade-like shape. Most species are found in the reef, and depending on the species, may feed on plankton, algae, sponges, hydroids or other invertebrates. Some species form mating pairs, while others form harems with a dominant male and several females. They are sequential hermaphrodites, and are born as females but when the dominant male is removed, one of the females will turn into a male. The juveniles of most species are black with blue and white lines, looking very different from the adults.
The Bluering Angelfish (Pomacanthus annularis) can be recognised by the diagonal blue lines on the sides of its body, a blue ring behind the eye and a white tail. This popular aquarium fish can grow to about 30cm long. The above photo was taken at Chek Jawa's rescue tank.
Family Pomacentridae
This family comprises the damselfishes and anemonefishes (or clownfishes), which typically have elongate or oval-shaped bodies, often marked with vertical bands or a series of stripes. Many species are highly territorial, especially during the breeding period. Due to their pretty colours and patterns, a number of species have become popular aquarium fishes, especially the anemonefishes. In some areas, the populations of some species have been greatly diminished due to over-exploitation for the aquarium trade.
The anemonefishes are among the few groups of animals that have developed symbiotic relationships with sea anemones, and are able to avoid their venomous stings. It has been suggested that they may have developed some resistance to the toxins of their host anemones, and the mucus coating on their bodies somehow deter the sea anemone from recognising them as prey. The relationship is a mutualistic one though - the fish gains protection living among the anemone's stinging tentacles, and feeds on any leftover food particles from the anemone's prey. In return, the sea anemone benefits from the anemonefish's territorial behaviour, which deters fishes that feed on sea anemones. In addition, the movement of the anemonefish improves water circulation and brings more oxygen for the host anemone, and its excretion provides nutrients for both the sea anemone and the symbiotic algae that live in the anemone's tissues. Anemonefishes are sequential hermaphrodites. They are born as males, and each population has a dominant female, and usually a main male partner. When the female is removed, the biggest male will turn into a female.
The Ocellaris Clownfish (Amphiprion ocellaris) can be recognised by having three broad white bars on a red to reddish-brown body. In Singapore, it is seen in several large sea anemones, such as the Merten's Carpet Anemone, Gigantic Carpet Anemone and Magnificent Anemone. This species grows to about 9cm long.
The Tomato Clownfish (Amphiprion frenatus) is usually seen in the Bulb-tentacled Anemone. It is orange, red or dark reddish brown with a long vertical white bar over the gill cover. It grows to about 14cm long.
The Yellow-banded Damsel (Dischistodus fasciatus) is dark brown to black with four yellow or whitish vertical bars. It gets to about 11cm long.
The Scissortail Sergeant (Abudefduf sexfasciatus) can be recognised by the five broad black bars on the sides of the body and a forked tail with a black stripe on each fork. It feeds on zooplankton and algae, growing to about 22cm long. The above photo was taken in Malaysia.
Family Pseudochromidae
Members of this family are largely elongate fishes, and some species may appear eel-like. They, however, have smaller mouths that extend to the beginning margin or middle of the eye, unlike true eels which have bigger mouths extending well behind the eye. Most species live in coral reef or rocky bottoms, feeding on small animals.
The Carpet Eel-Blenny (Congrogadus subducens) has an eel-like body and large lips, but has a smaller mouth compared to true eels (see above description for the family). The body tends to be brownish or olive-green with pale mottles. This species grows to about 45cm long.
Family Serranidae
This family comprises the groupers, sea basses and soapfishes. The body shape is rather variable, but most species come with a large mouth with thick lips. The dorsal fin can be single or divided into two fins - a spinous one and a soft one. The colour varies between the species, and many are able to change colours rapidly. They are generally found at or near the bottom, and feed on small marine animals. Many are protogynous hermaphrodites, meaning they are sequential hermaphrodites which mature as females first, but eventually turn into males. Some species are synchronous hermaphrodites with both male and female reproductive organs and can fertilise their own eggs. Most of these, however, spawn in pairs to have their eggs fertilised by the other fish. Some species form large schools during the breeding period for mass spawning. The groupers are among the most highly priced food fishes, and some species face the danger of being overfished. Several species are successfully bred in captivity and are important in aquaculture.
The Chocolate Hind (Cephalopholis boenak), so named for its colour, is usually brownish to greenish grey with dusky vertical bands over the body. The front half of the dorsal fin is spiny, while the other half has soft rays. It is a coastal species that grows to about 30cm long.
The Bluelined Hind (Cephalopholis formosa) can easily recognised by the numerous bluish stripes on a brownish body. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. It is a coastal species that grows to about 34cm long.
The Orange-spotted grouper (Epinephelus coioides), as the common name implies, has numerous orange to yellowish brown spots all over. The body is light greyish brown, with five slightly diagonal brownish bars on the sides. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. It feeds on small fishes and crustaceans, growing to about 120cm. This is an important species in aquaculture.
The Malabar Grouper (Epinephelus malabaricus) has numerous black and pale spots on its body and fins. The body is brownish, with a few slightly diagonal dark bands on the sides, which may fade off as the fish matures. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. This huge grouper is known to be able to reach lengths of over 230cm, and is an important food fish, often bred in fish farms.
The Yellow Soapfish (Diploprion bifasciatum) can be easily recognised by its yellow body with a dark brown bar across the head, and another across the middle of the body. It has two dorsal fins - a spinous one in front, and a soft one behind. It feeds on other fishes by swallowing them whole with its expandable jaws. This fish can secrete a toxic mucus when disturbed, and hence the common name "soapfish". It can grow to about 25cm long.
Family Siganidae
Members of this family have laterally compressed and somewhat oval-shaped bodies. They have small non-protrusible mouths, and generally feed on plankton or algae, though some also feeds on sessile organisms such as sponges and tunicates. The spines give painful, venomous stings, but these stings are generally not life-threatening. Many species are consumed, and most species are diurnal.
The White-spotted Rabbitfish (Siganus canaliculatus) is usually olive in colour with numerous pale spots, with a dark round blotch behind the gill cover. It feeds mainly on algae and seagrass. The Chinese call it "Pei Tor", which means "white belly", and consuming it during the Lunar New Year period (which coincides with the fish's breeding season) is believed to bring good fortune. This species grows to about 30cm long.
The Orange-spotted Rabbitfish (Siganus guttatus) can be identified by the many orange spots on its pale body. Unlike most other rabbitfishes which are diurnal, this species is reported to be active at night as well. It can grow to over 40cm long, and is consumed in the region. The above photo was taken in Malaysia.
The Double-barred Rabbitfish (Siganus virgatus) has two diagonal dark bands on the sides - one over its eye, and another just behind the gill cover. The back is yellow, while the belly is whitish. This species reaches lengths of over 40cm, and is consumed in the region. The above photo was taken in Malaysia.
Family Toxotidae
Members of this family are commonly called archerfishes for their ability to forcefully compress the gill covers so as to squirt a jet of water from their mouths to shoot down land-based insect prey. They generally are oval-shaped or rhomboidal, with dark spots or bars. The mouth is moderately large and protractile, with the lower jaw protruding. They are commonly seen in coastal waters, entering brackish areas such as mangroves and even freshwater sometimes. They are sometimes consumed in the region.
The Banded Archerfish (Toxotes jaculatrix) can be recognised by its straight back profile, greyish upperparts and pale belly with about four vertically elongate black blotches on the sides. Like other archerfishes, it is able to squirt water from the mouth to shoot down its prey, usually insects, from overhanging plants and other structures. This species can grow to about 20cm long.
References
Being ray-finned fishes, they are characterised by their fins being supported by rays of bony/horny structures, much like those paper folding fans supported by rays of sticks. Most species have a layer of scales covering their bodies, while some may have very reduced scales or no scales at all.
Here are some examples of marine perciform fishes that can be seen in Singapore.
Family Apogonidae
Members of this family, commonly called cardinalfishes, have two separate dorsal fins. They usually have ovate to elongate bodies, relatively big eyes, and a protruding lower jaw. While the colour may be quite variable, many species have dark bars or stripes on their body. They are mouthbrooders, with the males holding the eggs in their mouths. Most species are nocturnal, feeding on zooplankton and small invertebrates.
The Candystripe Cardinalfish (Apogon endekataenia) can usually be identified by the black spot on its tail, and the many thin horizontal stripes on its translucent body. It grows to about 10cm long.
The Checkered Cardinalfish (Apogon margaritophorus) has several broad, brownish to reddish horizontal bands on its body, and the band in the middle is broken by a series of pale spots, giving it an "airplane window" appearance. This species grows to about 5.5cm long.
Family Blenniidae
The true blennies are usually elongate, scaleless fishes with long dorsal and anal fins with flexible spines. They are usually bottom-dwellers, and hence the eyes are usually high up on the sides of the head to give them a good view of the surrounding. Most species feed on small invertebrates.
The Variable Fangblenny (Petroscirtes variabilis) has a pair of long curved fangs on its lower jaw. It is olive above and greenish-yellow below, with several large irregular dark blotches along the upper side. It gets to about 15cm long.
The Yellow Tail Black Blenny (Enchelyurus flavipes) is largely black with a yellowish tail. It gets to about 6cm long.
The Light's Rockskipper (Entomacrodus lighti) grows to about 11cm long, and can be recognised by the series of dark vertical bars along its body and reticulate pattern on its head.
The Striped Poison-fang Blenny (Meiacanthus grammistes) is a venomous blenny that can be recognised by the yellowish head and black horizontal stripes which are broken into spots towards the tail. This species grows to about 10cm long.
Family Callionymidae
Commonly called dragonets, members of this family tend to have elongate and moderately compressed bodies. The eyes are on the dorsal side of the head, since they are mostly bottom dwellers and this will allow them to have a good view of the surrounding. They have protrusible upper jaws, feeding mostly on small invertebrates.
The Mangrove Dragonet (Callionymus enneactis) is the only species known to be associated with muddy substrates, though it can be seen on sandy areas as well. It is can be recognised by having a narrow snout, dark saddles on the body, and dark markings on the anal fin. This species grows to about 8cm long.
The Smallhead Dragonet (Callionymus erythraeus) has a wavy line separating the patterns on its back, and dark markings on the anal fin. It can be differentiated from similar-looking species by the lack of a distinct dark spot at the base of the pectoral fin and anal - fin rays. This species grows to about 10cm long.
Family Chaetodontidae
Members of this family are commonly called butterflyfishes, as most species have eye-like spots and interesting patterns on their body, much like those on the wings of butterflies. They have small mouths located at the tip of a snout (which can be long or short depending on the species). The body is highly compressed. The eye-like spot serves to confuse predators as it resembles a fish facing the opposite direction. A predator which attacks the false "head" will only end up getting part of the tail fins.
The Copperband Butterflyfish (Chelmon rostratus) can be easily identified by the broad orange bands on the sides, the big black spot on the dorsal fin, and the long snout. It can grow to about 20cm long, feeding mostly on worms.
The Kite Butterflyfish (Parachaetodon ocellatus) has four brownish bars on the sides and a black spot the dorsal fin. It has a short snout, and feeds on sea anemones, coral polyps and sometimes, small invertebrates. This species can grow to about 18cm long.
The Eight-banded Butterflyfish (Chaetodon octofasciatus) has a short snout and about 8 narrow black bands on the sides. This species grows to about 12cm long. It feeds mostly on coral polyps. The above photo was taken in Malaysia.
Family Drepaneidae
Members of this family, commonly referred to as sicklefishes, are highly compressed laterally and somewhat disc-shaped. The spiny portion of the dorsal fin is separated from the softer portion by a deep notch. They have small, protractile mouths, feeding on small invertebrates.
The Spotted Sicklefish (Drepane punctata) and the Barred Sickelfish (Drepane longimana) have similar shapes and can only be differentiated by the patterns on their body. The former has numerous vertical rows of black spots, while the latter has numerous dark vertical bars. The above picture, unfortunately, features a sleeping sicklefish which has turned all black and hence it is not possible to tell the species. They are mostly found in coastal waters, growing to about 50cm long.
Family Echeneidae
Members of this family, commonly called remoras, have elongate bodies and flattened heads bearing sucking discs. These sucking discs allow them to attach to larger animals such as marine mammals, turtles and other fishes, effectively reducing the amount of energy used for moving around.
The Slender Shark-sucker (Echeneis naucrates) has an oval sucking disc on its head. While they are perfectly capable of swimming on their own, they are often seen attached to sharks, turtles and even ships. This species can grow to about 1m long, and feeds on small fishes, bits of its host's prey or the host's parasites.
Family Ephippidae
Members of this family are commonly called spadefishes as they are laterally compressed and appear somewhat spade-shaped. They are usually silvery or grey with darker bars or spots. The juveniles and the adults tend to have very different appearances. They mostly feed on seaweed and small invertebrates.
The Round-faced Batfish (Platax teira) has juveniles (see above) with very long dorsal and pelvic fins, but they eventually shorten as they mature (see photo of an adult taken in Malaysia). The adult is usually silvery or greyish with a convex lateral head profile. There is a dark vertical band running over the eye, and another just behind the gill cover. This species can grow to over 60cm long.
Family Gerreidae
Members of this family, commonly called the mojarras, have laterally compressed bodies that are usually silvery in colour. They have protrusible jaws, and the tail fin is usually forked. Most species live in large schools, though some species may live in small shoals or alone. They usually feed on small invertebrates which they grab from the seabed together with the sand, after which they will expel the unwanted sand and debris.
The above is a Silver-biddy (Gerres sp.) with silvery scales and yellowish fins.
Family Gobiidae
Members of this family, commonly called gobies, have short and broad heads, usually with the eyes located either on top of the head or high up on the sides. They are mostly bottom dwellers, and hence the higher location of the eyes allows them to have a good view of the surrounding. Many species can survive well in both brackish and sea water, while some may spend their entire lives in freshwater. Several species form symbiotic relationships and live with other organisms, such as shrimps, corals and other fishes - they aid in the detection of threats, remove parasites, or protect their hosts from predators. Some species, e.g. the mudskippers, can survive for long periods out of water by holding water in their gill chambers and/or breathing through the skin. During the breeding season, the males will usually guard and tend to the eggs.
As this is a rather large family, I have decided to provide more details and highlight the gobies I have photographed in another blog entry: Mudskippers & Other Marine Gobies (Phylum Chordata: Family Gobiidae) of Singapore.
Family Haemulidae
Members of this family are commonly referred to as grunts, due to their ability to produce a sound by grinding their teeth. The first half of their dorsal fins usually have strong spines. Many species have obvious, thick lips. They mostly feed on small fishes or invertebrates. A number of species are important food fishes.
The Brown Sweetlips (Plectorhinchus gibbosus) is usually brown, dark grey or black in colour. It has obvious thick lips and rounded tail fin. This species can grow to about 70cm long.
Family Labridae
Members of this family, commonly called wrasses, have protrusible mouths, obvious lips, strong jaws, and a single, long-based dorsal fin (in most species). They have very diverse feeding habits, and depending on the species, may feed on algae, plankton, and a variety of small animals.
The Green Pastel Wrasse (Halichoeres chloropterus) can often be recognised by the light green to yellowish body with intricate reticulate pattern of bands on its head. Some specimens may have a large dark blotch on the sides. This species grows to about 19cm long, feeding mostly on hard-shelled prey such as crustaceans, molluscs and sea urchins.
The Diamond Tuskfish (Halichoeres dussumieri) can be recognised by the dark and broad bars on the side, a dark spot on the middle of the front half of the dorsal fin, and another at the base of the pectoral fin. This species can get to about 16cm long.
Family Lethrinidae
Commonly called emperors, members of this family often have soft, obvious lips, a protrusible upper jaw, and molar-like or conical teeth for crushing their prey. Many feed on shelled animals such as crustaceans and molluscs, though some may feed on other fishes and invertebrates.
The Spangled Emperor (Lethrinus nebulosus) can usually be recognised by a few blue streaks radiating forward from the eye. The body color is yellowish or bronze, many of its scales have a whitish or pale blue spot in the middle. This species can grow to over 85cm long.
Family Monodactylidae
Members of this family are commonly called moonies for the round, strongly compressed body and silvery colour. Most species have prominently protruding dorsal and anal fins. They usually occur in schools in coastal areas, such as estuaries and shallow coral reefs, sometimes venturing into brackish and even fresh waters. Most feeds on plankton and detritus.
The Silver Moony (Monodactylus argenteus) is the only member of its family known to occur in Singapore waters. It has a silvery, somewhat disc-shaped body with protruding, yellowish dorsal and anal fins. It usually has a black vertical stripe on its head, running over the eye, and another over the gill cover. This species gets to about 25cm long. The above photo was taken in Malaysia.
Family Mullidae
Mullid fishes are commonly referred to as goatfishes due to the two long barbels on the chin. They generally have elongate bodies and a relatively big head. They usually inhabit shallow waters, and are often seen hunting at the bottom, using their barbels as chemical receptors to detect small animals hiding in the soft substrate. When a prey is located, the goatfish will poke its snout into the substrate to catch it.
The Freckled Goatfish (Upeneus tragula) can be recognised by a pair of barbels under the chin, dark stripes on the dorsal fins and tail fin, and a dark stripe along the side of the body from the snout to the base of the tail. This species reaches lengths of about 30cm, and is often used for human consumption. The above photo was taken in Malaysia.
Family Plesiopidae
Members of this family typically have elongate to oblong bodies with long fins, and hence they are also commonly called longfins. They are usually seen in coral reefs, feeding on crustaceans and molluscs.
The Comet (Calloplesiops altivelis) is a popular aquarium fish, and has been successfully bred in captivity. It can be recongised by its oblong shape, the numerous white spots, and the presence of an eye-like spot near the middle of its back. The eye-like spot serves to confuse predators as it resembles a fish facing the opposite direction. A predator which attacks the false "head" will only end up getting part of the tail fins. This species has also been observed to insert its head into a crevice when alarmed, exposing only its backend to mimic the head of a moray eel. This species can grow to about 20cm long. The above was an aquarium shot.
Family Pomacanthidae
This family comprises the marine angelfishes, which generally have highly compressed bodies. The dorsal and anal fins extend towards the backend, giving them an overall spade-like shape. Most species are found in the reef, and depending on the species, may feed on plankton, algae, sponges, hydroids or other invertebrates. Some species form mating pairs, while others form harems with a dominant male and several females. They are sequential hermaphrodites, and are born as females but when the dominant male is removed, one of the females will turn into a male. The juveniles of most species are black with blue and white lines, looking very different from the adults.
The Bluering Angelfish (Pomacanthus annularis) can be recognised by the diagonal blue lines on the sides of its body, a blue ring behind the eye and a white tail. This popular aquarium fish can grow to about 30cm long. The above photo was taken at Chek Jawa's rescue tank.
Family Pomacentridae
This family comprises the damselfishes and anemonefishes (or clownfishes), which typically have elongate or oval-shaped bodies, often marked with vertical bands or a series of stripes. Many species are highly territorial, especially during the breeding period. Due to their pretty colours and patterns, a number of species have become popular aquarium fishes, especially the anemonefishes. In some areas, the populations of some species have been greatly diminished due to over-exploitation for the aquarium trade.
The anemonefishes are among the few groups of animals that have developed symbiotic relationships with sea anemones, and are able to avoid their venomous stings. It has been suggested that they may have developed some resistance to the toxins of their host anemones, and the mucus coating on their bodies somehow deter the sea anemone from recognising them as prey. The relationship is a mutualistic one though - the fish gains protection living among the anemone's stinging tentacles, and feeds on any leftover food particles from the anemone's prey. In return, the sea anemone benefits from the anemonefish's territorial behaviour, which deters fishes that feed on sea anemones. In addition, the movement of the anemonefish improves water circulation and brings more oxygen for the host anemone, and its excretion provides nutrients for both the sea anemone and the symbiotic algae that live in the anemone's tissues. Anemonefishes are sequential hermaphrodites. They are born as males, and each population has a dominant female, and usually a main male partner. When the female is removed, the biggest male will turn into a female.
The Ocellaris Clownfish (Amphiprion ocellaris) can be recognised by having three broad white bars on a red to reddish-brown body. In Singapore, it is seen in several large sea anemones, such as the Merten's Carpet Anemone, Gigantic Carpet Anemone and Magnificent Anemone. This species grows to about 9cm long.
The Tomato Clownfish (Amphiprion frenatus) is usually seen in the Bulb-tentacled Anemone. It is orange, red or dark reddish brown with a long vertical white bar over the gill cover. It grows to about 14cm long.
The Yellow-banded Damsel (Dischistodus fasciatus) is dark brown to black with four yellow or whitish vertical bars. It gets to about 11cm long.
The Scissortail Sergeant (Abudefduf sexfasciatus) can be recognised by the five broad black bars on the sides of the body and a forked tail with a black stripe on each fork. It feeds on zooplankton and algae, growing to about 22cm long. The above photo was taken in Malaysia.
Family Pseudochromidae
Members of this family are largely elongate fishes, and some species may appear eel-like. They, however, have smaller mouths that extend to the beginning margin or middle of the eye, unlike true eels which have bigger mouths extending well behind the eye. Most species live in coral reef or rocky bottoms, feeding on small animals.
The Carpet Eel-Blenny (Congrogadus subducens) has an eel-like body and large lips, but has a smaller mouth compared to true eels (see above description for the family). The body tends to be brownish or olive-green with pale mottles. This species grows to about 45cm long.
Family Serranidae
This family comprises the groupers, sea basses and soapfishes. The body shape is rather variable, but most species come with a large mouth with thick lips. The dorsal fin can be single or divided into two fins - a spinous one and a soft one. The colour varies between the species, and many are able to change colours rapidly. They are generally found at or near the bottom, and feed on small marine animals. Many are protogynous hermaphrodites, meaning they are sequential hermaphrodites which mature as females first, but eventually turn into males. Some species are synchronous hermaphrodites with both male and female reproductive organs and can fertilise their own eggs. Most of these, however, spawn in pairs to have their eggs fertilised by the other fish. Some species form large schools during the breeding period for mass spawning. The groupers are among the most highly priced food fishes, and some species face the danger of being overfished. Several species are successfully bred in captivity and are important in aquaculture.
The Chocolate Hind (Cephalopholis boenak), so named for its colour, is usually brownish to greenish grey with dusky vertical bands over the body. The front half of the dorsal fin is spiny, while the other half has soft rays. It is a coastal species that grows to about 30cm long.
The Bluelined Hind (Cephalopholis formosa) can easily recognised by the numerous bluish stripes on a brownish body. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. It is a coastal species that grows to about 34cm long.
The Orange-spotted grouper (Epinephelus coioides), as the common name implies, has numerous orange to yellowish brown spots all over. The body is light greyish brown, with five slightly diagonal brownish bars on the sides. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. It feeds on small fishes and crustaceans, growing to about 120cm. This is an important species in aquaculture.
The Malabar Grouper (Epinephelus malabaricus) has numerous black and pale spots on its body and fins. The body is brownish, with a few slightly diagonal dark bands on the sides, which may fade off as the fish matures. Like other groupers, the front half of the dorsal fin is spiny, while the other half has soft rays. This huge grouper is known to be able to reach lengths of over 230cm, and is an important food fish, often bred in fish farms.
The Yellow Soapfish (Diploprion bifasciatum) can be easily recognised by its yellow body with a dark brown bar across the head, and another across the middle of the body. It has two dorsal fins - a spinous one in front, and a soft one behind. It feeds on other fishes by swallowing them whole with its expandable jaws. This fish can secrete a toxic mucus when disturbed, and hence the common name "soapfish". It can grow to about 25cm long.
Family Siganidae
Members of this family have laterally compressed and somewhat oval-shaped bodies. They have small non-protrusible mouths, and generally feed on plankton or algae, though some also feeds on sessile organisms such as sponges and tunicates. The spines give painful, venomous stings, but these stings are generally not life-threatening. Many species are consumed, and most species are diurnal.
The White-spotted Rabbitfish (Siganus canaliculatus) is usually olive in colour with numerous pale spots, with a dark round blotch behind the gill cover. It feeds mainly on algae and seagrass. The Chinese call it "Pei Tor", which means "white belly", and consuming it during the Lunar New Year period (which coincides with the fish's breeding season) is believed to bring good fortune. This species grows to about 30cm long.
The Orange-spotted Rabbitfish (Siganus guttatus) can be identified by the many orange spots on its pale body. Unlike most other rabbitfishes which are diurnal, this species is reported to be active at night as well. It can grow to over 40cm long, and is consumed in the region. The above photo was taken in Malaysia.
The Double-barred Rabbitfish (Siganus virgatus) has two diagonal dark bands on the sides - one over its eye, and another just behind the gill cover. The back is yellow, while the belly is whitish. This species reaches lengths of over 40cm, and is consumed in the region. The above photo was taken in Malaysia.
Family Toxotidae
Members of this family are commonly called archerfishes for their ability to forcefully compress the gill covers so as to squirt a jet of water from their mouths to shoot down land-based insect prey. They generally are oval-shaped or rhomboidal, with dark spots or bars. The mouth is moderately large and protractile, with the lower jaw protruding. They are commonly seen in coastal waters, entering brackish areas such as mangroves and even freshwater sometimes. They are sometimes consumed in the region.
The Banded Archerfish (Toxotes jaculatrix) can be recognised by its straight back profile, greyish upperparts and pale belly with about four vertically elongate black blotches on the sides. Like other archerfishes, it is able to squirt water from the mouth to shoot down its prey, usually insects, from overhanging plants and other structures. This species can grow to about 20cm long.
References
- Allen, G. R. 1997. Marine fishes of South-east Asia. Periplus Editions, Hong Kong. 292 pp.
- Baker, N. & K. Lim, (Vertebrate Study Group, Nature Society Singapore). 2008. Wild animals of Singapore. Draco Publishing and Distribution Pte. Ltd. 180 pp.
- Fisheries and Aquaculture Department, Food and Agriculture Organization of the United Nations. Fisheries and aquaculture fact sheets. Retrieved Apr 16, 2013, from http://www.fao.org/fishery/factsheets/en.
- Froese, R. & D. Pauly. Editors. 2013. FishBase, version (02/2013). Retrieved Apr 22, 2013, from http://www.fishbase.org.
- Kuiter, R. H. & H. Debelius. 2006. World atlas of marine fishes. IKAN-Unterwasserarchiv, Frankfurt. 720 pp.
- Lim, K.K.P & J. K. Y. Low. 1998. A guide to common marine fishes of Singapore. Singapore Science Centre, Singapore. 163 pp.
- Ng, H. H. 2012. The dragonets of Singapore (Actinopterygii: Perciformes: Callionymidae). Nature in Singapore, 5: 27–38.
- Ng, P. K. L. & N. Sivasothi (eds.), 1999. A guide to the mangroves of Singapore II: Animal diversity. Singapore Science Centre. 168p.
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