my oldest zebra all bloated

[bigpow]

He's the last zebra of the school I bought 6yrs ago.
Always have deformed spine, but lately as it's getting older/dying, it develops tumor-like growth



I've separated him on a separate tank, because I don't want the other fish to eat his carcass (w/ disease)

I had euthanized fish several times in the past, but it's been a while since I had to do it and especially with this old guy, I just don't have the heart to do it.

Any suggestions?

[Icewall42]

Looks like fluid buildup, though I can't be sure of the cause. Dropsy will usually pop out the scales, and I don't see that in your picture. If it's fluid buildup, I believe one way to help relieve that is epsom salt, but you might want to wait for someone else's opinion as I haven't had to treat bloating in the past, except for dropsy.