Bump on sterbai corys head

[16gallontanker]

Is this normal or some type of disease or a tumor only one has it out of the 5 I bought

 

[Colin_T]

looks like a genetic deformity. the fish probably had it from day one and it won't change. You could take it back and swap it for a fish that isn't deformed or leave it in the tank where it is.

 

[16gallontanker]

I'll leave it because I bought them online and thanks for your response