Glofish Tetra With Cysts

[juju]

My glow fish tetra has a cyst on both sides between the anal fin and the tailfin. They appeared to be transparent with tiny black balls in them. They’ve been there at least two months. There are no other symptoms. The fish swims fine and he’s eating anybody. Have any idea what they could be?

 

[Andy Sager]

Unfortunately, genetically modified fish can come down with all kinds of things. There's not much you can do for tumors so as long as the fish eating and swimming fine, enjoy it for as long as you have it. If the fish starts to act differently or starts getting picked on by the other fish, that's your clue to euthanize him.