What is this black colored fin on my Glofish Tetra?
I have this black colored fin on my Glofish tetra. It started out as a little black dot on the fin, but now it has covered the whole fin. What is this? Any help would be much appreciated. Thanks in advanced.
That is the adipose fin of the fish. Considering the fish is a color morph of the Black Tetra (http://animal-world.com/encyclo/fres...WFCh_C2975.jpg) you can see in that pic that it's a natural color for the unchanged fish. My guess is that it's just a throwback to the original coloration of the genetically original fish.