This is what I was thinking as well! When you see it from the underside, it looks like a prolapsed rectum. Unfortunately, I can't get a good picture of that because I don't have a macro lens. What should I do? Let the fish live out its life in quarantine?
I would probably keep it in QT for a couple of weeks with daily water changes and see what happens. If it is the remains of a fin, it should start to heal up pretty quickly with clean water and maybe some pima/melafix (can't remember which one atm). If it hasn't started to heal after a couple weeks... it may be time to euthanize. :uhoh:
After inspecting my fish, I am 95% sure that is the anus. I can assure you that it is definitely not an injured fin. Her fins are completely intact. Unfortunately, you cannot tell that from the picture because her fin is black and clear against a black background. Also, whatever it is is quite wide and cylindrical, not at all like a fin. Thanks for the suggestion though. Keep 'em coming!
I'm sorry for your troubles. I've seen a case of prolapsed intestine that recovered after fasting for a couple of days and then feeding nuked english pea.
This is what it looks like. Callamanus worms look more... worm like... this looks more like an intestinal prolapse.
The fish may not recover... but it's worth a try to fast for a few days... then feed english pea that is nuked in the microwave, remove the skin, it needs to be slightly mushie... and you could add some garlic juice to make it irresistable....
I don't know if this will do the trick... but I can't think of any other suggestion. I hope that your fish will recover from this.
Why the instance on worms? appears to be a prolapse and I would treat accordingly. Clean water, and fasting. You may have to euthanize if she deteriorates, but for now there is no reason to suspect worms.
Why the peas I wonder? And why English peas? Do you think you could use soaked split peas since they are just dried shelled peas- becasue peeling peas seems like a lot of work. I've never tried it, I am just guessing. can you just squeeze out the insides?
My guppy had some sort of prolapse. It looked exactly like that with the red thing coming out. I had to net her out to see and this was a picture of her. There isn't really a way to treat it. Mine lasted about a month. She just died this week but the prolapse disappeared and then reappeared from time to time. I thought it was worms but she seemed to be the only one affect. I doubt the prolapse killed her but I think it was from my new fish beating her up.
A few times it looked like it was coming out from her stomach and not her butt like yours.
Here's the pic: (Had to take her out of the water but she seemed fine afterwards)
ive seen this before at work, not sure what it is, but i feed it sweet peas with no extra sodium added, and treated with Lifeguard, 6 of the 10 recovered, the other 4 died, not sure if its the same thing though.
