I came home yesterday and noticed one of my veil tails was swimming upside down,the two year old, and had lost most of its scales on sides and belly.
did immediate water changes and filter cleaning.
then noticed this evening the plecostomus was actually eating the scales on its sides well it is immobilized.
I will move plecostomus to new tank, well veiltail recovers.
will veil tail survive with out its scales well recovering from swim bladder disease
or should I put it out of its misery.

Not too terribly long ago one of my ranchu suffered a similar fate with a pleco I thought would be safe. I really thought the fish would die, or at least die because of a secondary infection. I moved the fish to a 10 gallon tank by herself and made sure to keep her water perfect (0 ammonia, 0 nitrite, 5 nitrate) and treated the tank with Melafix (antibacterial remedy) The first thing to happen was for her sides to get "fuzzy" (but not like a fungus!) looking. I believe this was the dead tissue starting to come off. The next step, that began to come off and underneath was what resembled scales to an extent but solid white and not individual. She began getting black spots while she was healing. Now she has grown most of her scales back and is doing fine.

Keep her safe from parasites, bacteria, and anything else that will be trying to live in/on her in her weakened state. It will take a long, long time, but in good water she should be alright.

Now to find out why she was floating in the first place? Perhaps someone else can help you more than I.

Good luck!

Welcome to the site.

Sorry to hear about what happened. We have alot of members who have this problem. It is good you moved the pleco, he shouldn't be in with the gf. Once they start doing this they continue.

As for the poor little veil, keep the water params perfect (by the way what are they?) and keep the tank calm and dark to comfort him/her.
Perfect water is the best for healing, if there are open sores you may want to put the fish on a medicated food to ward off infections.

Hope she/he makes it for you.

Hello, do you have any updates for us?