Home >> Science & Nature >> Animals & Science

What Makes a Fish a Cichlid?

Cichlids are a diverse family of freshwater fish that are part of the Perciformes order. The multiple species of cichlids, found in freshwater lakes on four continents, make them difficult to identify. For those interested in keeping cichlids in an aquarium, it may be difficult to discover the exact cichlid species, even when they're purchased from a pet store, as retailers often don't properly label cichlids. Once you've determined that a fish is a cichlid species, online forums are helpful in determining what specific species the fish is.

External Identifying Features of Cichlids
- Cichlids share only a few key traits, one of which can be identified by examining their jaws: Cichlids have teeth in both their upper and lower jaws. The fish use these teeth to process food; because of their extra teeth, they're efficient feeders. Other small visual cues that can help to identify them upon close inspection are the single nostrils they have on either side of their head, as opposed to two.
Internal Identifying Features of Cichlids
- Internally, cichlids have other traits that help identify them. If you have an opportunity to dissect a dead cichlid, you'll notice the following traits. Their otoliths, which are bones found in their inner ears, have a distinctive shape. Also, unlike all other known fish, their small intestines start on the left side of their stomachs, not the right. When dissecting the jaw of a cichlid, you see that its lower jawbones, known as its pharyngeal bones, are fused into a single tooth-bearing structure: Complex muscles allow both the upper and lower pharyngeal bones to become a second set of jaws. Teeth can also be found in the throats of cichlids.
Variable Traits in Cichlids
- Aside from these key traits, there aren't any other visual cues to help identify cichlids. Their shapes and sizes are extremely variable, as is their coloring. The smallest cichlids, known as Apistrogramma ciclids, are only 1 inch long, while some of the largest cichlids can be longer than 3 feet. Their bodies can be long and thin or compressed and round. Cichlids have stripes, spots and a variety of other coloring distinctions based on their specific species.
Different Types of Cichlids
- Cichlid enthusiasts divide cichlids into three categories based on the regions they come from. There are American cichlids, which reside in both North and South America; African cichlids; and Asian cichlids. Angelfish and discus are popular American cichlids, while tilapia and a variety of fish found in the Rift Valley make up the African cichlid group. Although cichlids tend to be aggressive fish, African cichlids are the most friendly; American cichlids are the most aggressive.

Animals & Science