5. Nudibranch

A nudibranch is a member of what is now a taxonomic clade now, rather than a fish. Nudibranchs are often called ”sea slugs“. This has led some people to assume that every sea slug must be a nudibranch. Nudibranchs are very numerous in terms of species, and are very attractive and noticeable. Among this group can be found the most colorful creatures on earth.

6. Symphysodon

They all have a compressed body shape and the extended finnage is absent, that’s why they have a more rounded shape. It is this body shape from which their common name, “discus” appeared. The sides of the fish are frequently patterned in shades of brown, green, red, and blue.