Help

[Elvalle69]

My zebra eel has a bump what do I do

 

[Old Fritz]

could be a number of things. it could be a tumor (unlikely to happen overnight), internal bacterial infection, parasite under the skin. If you have anything venomous in the tank it might be because he poked that fish like a lionfish. what is his activity like? is he still eating? what are his water parameters? what are his other tank mates? Did anything die in your tank recently?