The new species has been found in two small isolated waterways in Brazil's Atlantic Forest, according to a study.

As a fish swims through water, the dorsal fin stabilizes it and keeps it from rolling over. But over time, many fish have evolved different uses and appearances for these skin flaps.

Mesmerizing, kaleidoscopic, and fabulously exotic, the huge variety of types of saltwater fish to pick for your aquarium will ...

The fish was “slender” and “fusiform,” and it had an adipose fin, a fleshy dorsal fin without bony rays that is common in fish like salmon, according to the study.