Bladder disease and missing fins?

Question
Hi, thanks for taking the time to read my question. I have a Black Moor Goldfish that I rescued from Walmart about 3 weeks ago. He is in a 20 gallon filtered tank with another goldfish. Temps range from 70-75 degrees. I do not use any kind of aqauarium salts.

Recently he lost his back fin (possibly from the filter, but I'm not 100% sure) and he has been floating face down in the tank. At first I thought he was dead, but upon closer inspection his gills were moving. I nudged him with the fish net and he began trying to swim upright, but he just couldn't do it. Now he's back to being facedown in the tank. I thought it was because of his missing tailfin, but now I think it might also be a swim bladder disease. Is there any chance that he will recover or would euthanasia be a more humane option at this point?

Answer
Hi Brittany.  Kudos to you for rescuing the fish from Walmart.  I'm against Walmart being allowed to sell fish, for reasons you're obviously aware of.  But I'm sorry to hear he's under the weather.

If you do not already use aquarium salt, I would add a little less then 1 tablespoon per 5 gallons of water he's in.  Aquarium salt has healing qualities that can help him pull through this.  The thing you really have to worry about at this point is secondary infection.  You need to get a broad-spectrum antibiotic and use that for any infection which may be brewing as a result of his fins being torn.  

As far as the possible swim bladder.....try feeding him a couple of peas with the outside shell peeled off, then withhold food from him for a day or 2.  If he rights himself, that's a good thing. It would be safe to assume that it is/was swim bladder and maybe it will be gone.  It may come back though.  If it does, just repeat from the beginning.  You can also try feeding every other day.  I know that will be hard because they are such beggars, but it will help.  If it is an infection, the medications you are going to put him on should help also.  

There is no way to tell exactly what is causing what, or if he will pull out of it.  It's that proverbial saying "time will tell".  Just do what you can for him, and if it starts looking too bad or if you think he's in pain and don't want to prolong anything, then you have to decide whether or not to euthanize.  This, of course, will be totally up to you, as only you can make that decision.  It's a hard place to be in, I know.

If there is anything else I can do for you, or help you with, please get back to me.  Please also keep me updated on his process.

Best of luck.   ;o)