Divewerkz would like to give you an overview about commonly encountered marine life in South-East Asia to make your future dives even more rewarding.

Why ID fish?
To many divers identifying fish may be an overwhelming task. But, believe it or not, with the right approach, it’s fun and easy.

Better dives
When you are able to recognize fishes you have a mental description of the dive. Remember those times when you get frustrated describing a fish and nobody seems to understand what you are talking about? Knowing the names of fishes helps communications with other divers and you get more out of the dive.

Aid navigation
Certain fishes are territorial and when you recognize them they become the landmarks for your course of travel. Fishes such as clownfish and damselfishes live and often feed within a certain area.

Safer diving
Knowing which fish is dangerous is obviously important. Scraps with fishes such as surgeonfish, stonefish or scorpionfish can leave you with serious injuries.
 

How to ID fish?

Shapes
The first step to identifying fish is to put them into their family group. Classifying with shape and general features is the easiest way to identify the family they belong to.

Size and special markings
Within the same family, some fishes look incredibly identical. If this is the case, take note of the size and confirm it with the size in fish ID books. Also take note of specific features and/or markings on the fish. To do this it helps to learn the parts of the fish (see below) and jot down the markings observed on a slate.

Depth and habitats
Fishes have distinct habitats. Some fishes favour deep waters whilst others stay within 20 metres from the surface. Some are primarily coral dwellers such as anthias, whereas fishes such as goatfish and gobies stay mainly on sandy bottoms.

Below we offer you some brief explanations about fish groups along with their typical outlines to help you identify them more easily. Click on the fish outline (they are not to scale) to be directed to a website with a lot of pictures of the respective species.
 

Batfish: Highly exaggerated dorsal, anal and pelvic fins. Young fish occur singly or in small groups and stay near reefs. In Asia, the Pinnate and Teira Batfish are commonly sighted. The juveniles have very long fins that become proportionally shorter as it grows.
Did you know that some juveniles mimick deadleaves (Orbicular Batfish) or toxic polyclad flatworm (Teira Batfish) as camouflage?
 

Butterflyfish: Round and small and have concave foreheads. They often have snouts for feeding from crevices and corals. Butterfly fishes are renowed for their striking colours and graceful swimming patterns. Most are active during the day and stay within 20m depth. Many feed on corals and small invertebrates. They are often seen in pairs.
Did you know that some butterflyfishes such as the Spot-Banded Butterfly are know to form permanent relationships? If one dies, they never find another mate.
 

Bannerfish: The bannerfish belongs to the butterflyfish family. They have unusually long dorsal fins and are usually not more than 20cm long. At places like Sipadan and Layang Layang, the schooling bannerfish form a beautiful picture against the bluewater backdrop.
 

Angelfish: They have long dorsal fins and rounded foreheads. Most angelfish are found in boulders, caves and large crevices. Most stay within a certain territory and they are one of rare species that feed on sponges among other things like algae, zooantharians, tunicates, gorgonians, hydroids and seagrasses. During their growth from juvenile to adult, they take on the most dramatic transformation.
Did you know that the blue-ringed and six-banded angelfish can make clicking and drumming noises? Keep your ears peeled when you see them next time...
 

Surgeonfish: Somewhat horse-shaped or sloping face with spines sticking out from each side of their tail base. Most surgeonfish are docile and travel in schools. They feed on algae and seaweed.
When in close proximity with divers, such as fish feeding session, take care that they don’t come too close as their scalper-like spine on each side of their tail can inflict nasty wounds.
 

Jacks: Also called trevallies, usually silver or blueish in colour, seen in open water at reef’s edge. The most frequently sighted jacks are the big-eyed, golden, black and blue-finned trevally. The largest trevally, the Giant Trevally is an awesome sight and can grow up to 1.7m and weigh up to 170 kg. In places such as Sipadan and Layang Layang you can often see trailing sharks under a group of hunting travellies hoping to feed of the scrapes of the hunt.
Did you know that during mating season, the silver jack changes its sex and turn totally black in colour? The black and silver couple stays together for a period before mating.
 

Barracudas: Long cylindrical and silver with faint markings. Large mouths with visible teeth. Large barracuda tend to travel alone, but smaller species may gather in groups. Schooling barracudas can number to a thousand and are a spectacular sight!
 

Snappers: Long tapered bodies and heads that slope towards the mouth. Common commercial fish. Most snappers are brightly coloured and active predators of smaller fishes, crabs shrimps, gastropods, cephalopods and planktonic organisms.
 

Sweetlips: Look quite similar to snappers, their most distince feature is their lips which seem to be swollen. Often found hovering under coral tables or just above reefs.

Damselfish: Small, oval fish that dart in and out of crevices on the reef. Algae feeding damselfishes are very territorial of their food turf. Damselfishes make up one the most abundant groups of coral reef fishes. Most are small, and are not bigger than 15cm. It is believed that the drape coloured species feed on algae and their brightly colour counterparts feed on plankton.
 

Groupers:  They have bigger and rounder bodies with large mouths and lips. Commonly in brown, black or reddish colour with splotchy markings. Mostly solitary and stay in shadows of sloping reefs.
 

Fairy Basslets: Also know as Anthias. Very tiny and colourful fish that brighten the reefs as a rainbow does. They often stay in large aggregations and swim in tandem against the current above corals.
Did you know that Fairy Basslets have a harem-type of social structure? There is only one male surrounded by a group of not less than 10 females. When the male dies or is eaten, the leading female will change into a male within 2 weeks and assume his role.
 

Parrotfish: Beak-like teethplates and rainbow colours, much like parrots. They swim with their pectorals fins, and often scrape algae off hard surfaces. Like wrasses, parrotfish undergo female to male sex change according to growth stage. The colours between the sexes can be so different that they have long been regarded as different species!
Did you know that many parrotfish sleep in a strange cocoon-like mucus envelope to mask their scent from predators such as eels?
 

Wrasses: Generally smaller than parrotfish, usually foraging through sand and the reefs. Wrasses make up the second largest group of reef fishes after the gobies. They are very active and are constantly foraging for small crabs, shrimps, worms, and other small bottom dwelling invertebrates.
 

Squirrelfish: Pronounced rear dorsal fin that sticks out like a squirrel and very large glassy eyes. Hidden in crevices and under ledges. Squirrelfishes are nocturnal and during the day, they are found hidden inside caves or under large crevices. They come out to hunt shortly after sunset. They feed primarily on night animals such as crustaceans and echinoderms.
 

Bigeye: Bigger eyes than squirrelfish, with continuous dorsal fin and they appear less scaly. Like squirrelfishes, they are nocturnal and feeds on cephalopods, crustaceans and fishes.
 

Cardinalfish: Small and reddish, with short snouts and 2 separate dorsal fins. They are small reef dwelling fishes and crustaceans. Some species, form large shoals over entire coral formations.
Did you know that male cardinalfishes incubate fertilised egg mass in their mouth for days until hatching?
 

Blennies and Gobies: Long bodies and generally perched on their pectoral fins. Most blennies are less than 15cm long, and are bottom dwellers, feeding on small invertebrates, algae and bottom detritus. Several species such as the False Cleanerfish have large teeth of the lower jaw that is used mainly for defense.
 


Flounders: also know as Flatfish, are amazing bottom-dwelling creatures, masters of camouflage. They change colour to blend into the bottom colours. Both their eyes are on the same side and they move independently.
Did you know that flounder larvae looks exactly like fish larvae? However, when they grow, their bodies become compressed and one of the eyes migrate to the other side.
 

Scorpionfish:  Stocky and rough bodies, with spiny dorsal fins that carry venom. Still and pretends to be a piece of rock. Scorpionfishes varies from mottled brown colour (for those found in rocks) to bright red in colour, found in caves and deeper sections of the reef.
 

Lizardfish: Elongated bodies and large upturned mouths. Often perched motionless on corals and bottoms. Lizardfish look somewhat like a cross between a monitor lizard and a chameleon. They lay like a monitor lizard with their bellies on the coral, and pretend like they are part of the "furniture".
 

Frogfish: Bulky bodies with large upturned mouth. Blend well with bottom, and often motionless. Some have appendage that dangles in front of their mouths, which baits unsuspecting fish.
 

Filefish: Oval or diamond shaped with rough textured skin. Elongated pointy dorsal fins. Filefish are the sweetie pies of the reefs. They move daintily with slow measured movements. When there isn’t any big fish action to watch, the filefish can provide amusement and enjoyment.
 

Triggerfish: Oval or diamond shaped bodies with elongated pointy dorsal fins similar to a gun’s trigger. Most triggerfish species are solitary in habit, and they use their strong teeth to crush hard-shelled prey such as crabs and molluscs. Most triggers are same and harmless such as the pretty Picasso Triggerfish. In Asia, the larger species such as the Yellowmargin and Blue-finned triggers should be treated with respect, particularly during their nesting period.
Triggerfish lay eggs that are aggressively guarded by the female. Divers should swim cautiously around their area as they are know to attack any divers deem a threat to their young.
 

Pufferfish: Round bodies and can inflate their bodies when threatened or scared. They are strange creatures with bodies encased in a bony carapace and fins are relatively small. They are slow swimmers, but capable of short, rapid bursts. The spiky ones are called Porcupinefish. The non spiky puffer has no scales and have beady eyes. Under no circumstances should puffers be eaten. Some carry toxins that may cause serious illness and death.
 

Trunkfish/Boxfish and Cowfish: Boxy and rectangular bodies. Cowfish have two ‘horns’ on their heads. Common species in Southeast-asian waters are the Striped trunkfish and Black-saddled Toby.
 

Goatfish: Long cylindrical bodies with two widely seperated dorsal fins, and a pair of long chin-barbels that are used for detecting food in the sand. The barbels are also used by males to attract females during courtship. When they are not used, you can hardly see them as they are tucked tightly under their chin.
 

Trumpetfish: Long tube-like bodies with long pouty mouth. They stalk by handing head down, often near corals to camouflage themselves. A common species is the Painted Trumpetfish.
 

Eels:  Snake like and often hiding in crevices and holes. Eels are shy creatures in the day, and at most, peek out of their crevice. However they transform to another creature as night falls. Eels have been found free swimming in the night, foraging for food such as small fishes. With their gaping mouths they are excellent photographic subjects.
 


Fish parts
 

1 barbel
2 preopercle (cheek)
3 operculum (gill cover)
4 pelvic fin
5 pectoral fin
6 spiny dorsal fin
7 lateral line
8 soft dorsal fin
9 anal fin
10 caudal fin (tail)

 


Lionfish showing off