The red shading fades into dark fins, and their black eyes are rimmed in orange. Oscars, like most fish, are timid when they're first introduced to a new aquarium. After they've had a few days to ...

which is the fin underneath the fish. Their dorsal fins, or the top fin, are red, black and yellow. The Sipsey Fork darter has a yellow-green fin, with the base being a “reddish hue visible from blood ...