post image

The External Anatomy of a Fish

If you’re someone who’s going to care for your own fish instead of having a service maintain your tank, you need to know a little bit about fish anatomy. Here are some of the basic – and not so basic – external fish parts.

Remember that unlike humans, whose basic form as a species is upright, fish range much more in shape, and even in which body parts they have. But, generally speaking, they’re similar enough and easy to identify.

The Shapes of Fish


Perhaps the most familiar parts of a fish are its fins. Fins are not much more than sheets of skin that hang from the fish and are supported by a structure of rays to offer a fish stability when jetting through the water. These rays are made from organic material that can be soft or hard. Throughout evolution, some fins have evolved into protective devices like spines, or into a bait decoy that lures the prey closer to a hungry mouth.
The Extras

Some fish have these various decorations and adaptations, many do not.

The tail fin, also called the caudal fin, can be either a single fin or forked. If it is forked, the upper and lower parts of the fork are called the upper and lower lobes, respectively.