What Are the Different Types of Fish That Exist Today?

You won’t find many more animals with greater varieties than fish. Given that where they live covers far more of the earth than we do, it is no surprise. 

But even so, they still have an air of mystery surrounding them. For example, even today, new species are still being encountered.   

But did you know that even though there are 32,000 types of fish out there, they can be split into just 3 simple groups?

After this article, you will be able to easily identify the 3 main different types of fish, whether you are in the best aquarium in town or looking at one on your dinner plate.

Bony Fish

Starting with the most common, when we think of a fish in a traditional sense, what most of us imagine is a bony fish. 

Why do we say that? It’s because bony fish have many of the defining “fish” features that we expect, such as paired gills and the flaky scales that make up a fish’s body. 

So why bony fish? Don’t all fish have bones? Technically no. While some don’t have bones at all, the bones found in bony fish have similar characteristics to humans in that they have collagen and are calcified, giving them those harder bones that we all try to avoid if eating them. 

Given that there are over 28,000 bony fish species, it is unsurprising that they have a wide range of predators, such as birds, amphibians like the leucistic axolotl linked here, and obviously, the most dangerous of all, humans. 

Types of fish that fall into this category include all the best goldfish, salmon, and clownfish, to name a few. 

Cartilaginous Fish

The next up is cartilaginous fish. These vertebrates are again defined by the makeup of their bones. While bony fish have skeletons made of tough hard bones, cartilaginous fish have skeletons made of cartilage, the same stuff that is in our ears, noses, and joints. 

This makes a big difference in the way they can move in the water. Cartilage is much lighter and flexible, meaning that these fish are faster and more agile. This makes sense when we realize exactly which types of fish fall into this category. 

Cartilaginous fish are usually the best fish operating as predators on the open seas. All the shark varieties are included here, along with rays. 

Jawless Fish

Lastly, we come to the most unusual types of fish around, jawless fish. 

Belonging to the agnathan group, these fish don’t have jaws (unsurprisingly) but feed either through suction or by having a filter in their mouth. This is the smallest group by far, with only about 120 types of fish falling into this category. The most well-known are likely the hagfish or the lamprey. 

These fish are also identified by having a prominent presence of slime on them due to them having more active mucous glands. They don’t have scales, and therefore they have more traditional skin to the touch. 

Although they do stand out as different from the other types of fish, they do have something in common with rays and sharks, which is that their skeletons are made out of cartilage. 

How Many Types of Fish Did You Know?

The world underneath our seas is vast and mysterious. We hope that this bite-sized article on the wide variety of different types of fish has done enough to fill you in our at least one small aspect of it. 

We hope you enjoyed this post. For more great informative posts like it, please check out the other articles on our site! 


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