How to ID fish. What to look for....

When identifying a fish, there are several things that you should be looking for. Below are the terms used in most of the Fish ID books and guides for the different "parts" and markings of a fish. Please note that the pictures below are not of an actual fish. I've just used a generic looking fish for an easier comparison.

A 1 page printable version of the 4 diagrams below can be downloaded here for free. This file requires Adobe Acrobat to open and print.

Fish Anatomy:

When looking at a fish, it is important to take note of the anatomy of the fish. Notice the Dorsal, Caudal, Ventral, Anal, and Pectoral Fins. Some fish have a stubby Caudal Fin, while others are wider and forked. Are there significant markings on any of these fins? Some fish have a spiky dorsal fin, and some don't.

Also, does the fish have a barbel? If so, you can probably narrow it down to the Goatfish family.

When looking at a fish, also try to observe the proportions and general shape of the body.

• Is the fish long and slender like a Wrasse?
  
  
• Is it boxy shaped like a Puffer?
  
  
• Is it shaped like a flat oval disc or plate like a Butterflyfish?
  
  
• What is the shape of the tail? The head? The mouth?

Another thing to look for is what the fish uses to swim. A Parrotfish or Wrasse uses it's Pectoral Fins to swim, while a Triggerfish uses it's Dorsal and Anal fins to swim, and of course many fish use their Caudal (Tail) fin to get around.

Fish Markings:

Although color can often play an important role in identifying a fish, it is most often the markings on the fish that help you find the identity. If you rely on colors alone, you'll often be back on the beach, scratching your head wondering what that fish was.

Take a look and try get used to the markings below. The names used for these markings are the most used in Fish ID books. When observing a fish, are those lines on it horizontal? Vertical? Angled? And what about that spot? Is it a single spot? Does it have a ring around it? Is there more than one?

And Where are these spots? Where are the lines? These are some things that you should be thinking of as you try to remember what a fish looked like. The more you get used to looking for these things, the easier it will be to spot them out in a book.


Click on a marking on the images below to see a sample of that particular marking on a real fish!