Fish ID Basics
To more accurately describe fish species, which can help with their identification, learn the names for the different parts of a fish’s body! You will come across many of these throughout the species descriptions on this web-portal.
For most people, colour is the most obvious and prominent feature of a fish. While colour can be a helpful clue to identifying a fish’s species, it is also important to keep in mind that colour changes and individual variations are common in many reef fishes. For example, species can often look quite different between daytime and nighttime, and throughout different stages of life.
Fish that are dead will also look very different to when they were alive.
Freckled goatfish
Chinese demoiselle
Chinese demoiselle
Chinese filefish
Chinese filefish
Freckled goatfish
Russells snapper
Chocolate hind
Chocolate hind
Painted sweetlips
Painted sweetlips
Painted sweetlips
Painted sweetlips
Russells snapper
Russells snapper
Dark cardinalfish
Dark cardinalfish
Dark cardinalfish
Some species are blessed with unique looks!
Here are some examples of species that have something no one else has.
Two long barbels protruding from under the lips, used for searching through sand.
A pair of horn-like features above the eyes.
Two to three long, flowing filaments from the caudal fin.
A long, extended first dorsal fin.
A very tall, whip-like dorsal fin.
One prominent dorsal spine protruding from above the eyes.
Four pairs of barbels underneath the mouth.
Multiple cirri around the bottom lip and chin.
There are different types of patterns that appear on fish, many of which have specific names.
Just like with colour, patterns can sometimes appear differently on the same species due to day or nighttime colour variations, or other factors. But for some species, some patterns almost never change, giving us a relatively reliable identification feature. These are described in the species profiles for each fish.
Threespot Grouper
Sailfin tang
Clark’s anemonefish
Doublebar cardinalfish
Yellowstripe scad
Doederlein’s cardinalfish
Twostripe goby
Yellowstreaked snapper
Threespot dascyllus
Pearl-spot chromis
Threespot dascyllus
Mirror butterflyfish
Ring tailed cardinalfish
Honeycomb grouper
Longfin grouper
Starry goby
Red seabream
Red seabream
If you want to really get down to the science, you can start off by looking at the shape of the fishes. Species in the same family will often take on similar body shapes. While this method is accurate, it definitely isn’t easy!
Click on the fish to learn more about them!
Some species exhibit behaviours which are relatively unique. Familiarizing with the behavioural tendencies of specific species can be a helpful aid in identification. See the examples below!
Each dive site provides a range of habitats for species to choose from. Knowing the habitat preferences of fishes can give you a hint to what you might find at different dive sites!
