Hi all, I'm having a little issue with one of my pygmy corys that has me a bit worried. They live in peace with my male doubletail betta in a planted 10 gallon.
Today however, I noticed one of the little guys has what appears to be a nipped tail fin. Its a really clean edge, hence why I'm inclined to believe it was a bite rather than something like fin rot or a tear. If I'm wrong, please feel free to correct me on this. However, I've never seen anything to suggest aggression from my betta so I was shocked to see this kind of injury... maybe he got it caught on something or injured during a gravel vacuum? :/
He's the smallest of the group by quite a bit - 2 big girls in particular dwarf him and seem to be growing everyday. He honestly hasnt really grown at all, he's maybe a half inch long and seems skinny compared to some of the bigger cories.. not sure if this is a male/female thing, or if there is something else going on, but I felt like it was worth mentioning.
He's still eating and swimming fine, it just seems to take him a slight bit more effort because of the nipped tail. My betta is leaving him alone, but he seems to be largely keeping to himself and not shoaling with the others.. though I always seem to have 1 or 2 or dont join in.
I took a picture as best I could of the little guy and outlined the tail so its easier to see.. they're lightning fast so its super blurry unfortunately:
I guess my question is how to proceed from here. Will it grow back alright? Is there anything I can do to help speed this along? Is his small size and general lack of growth something to be concerned about? Should I drain some of the tank so he doesnt have to work so hard to reach the surface while he heals? Should I move my betta to a separate tank until the cory starts to heal? Is it likely my betta caused this, and if so should I just separate them permanently?
Thanks in advance!