Fire eels are part of the “spiny eels” family, called Mastacembelidae, which gets its common name from small spines on the species’ backs. Although they have elongated bodies, and it’s in their name, fire eels are technically freshwater fish rather than true eels. Fire eels have pointed snouts, and their bodies are dark brown with some red and yellow stripes.

Fire eels often seek shelter and bury themselves in the substrate (the material used at the bottom of aquatic habitats), so they can be difficult to spot sometimes.