One of my two bloodfin tetras has a swollen anus. It doesn't look like a parasite because I can't see a seam between the swelling and the fish, however I could be wrong. What could cause this? Any solutions?
Its hard to tell from that picture. It could be a tumor or protruding intestines but it could also be a parasite. Here is a link to a thread I started when I had Camallanus. Does it look like any of those pictures?
It seems like an inflammation because it is slightly red and wasn't there a week ago. Also the fish seems to twitch/shudder sometimes.
I drop a slice of blanched zucchini in the tank every two weeks as well, and leave it all day and overnight before removing it. It's usually about half eaten, and I've seen everyone get a piece of the action, including the bloodfins.