So he has AQ salt in his hospital tank, and no salt in his 10g? You need to cut down the AQ salt in his hospital tank daily until he's at zero salt. Then you switch to the 10g tank. The shock from going to a tank with salt to a tank without is probably what's stressing him out.
His hospital tank didn't have salt in it. As soon as he freaked out, I put him into water without salt, and I haven't used the salt since. He just went from unsalted, dechlorinated water in the hospital tank to unsalted, dechlorinated water in a tank-gallon tank. =/
Awww.. =[ It does make sense that bettas can be allergic to things, just like humans... I had never thought of that. Poor little guy.
I just looked at him, and he's still a bit pale, but nothing like yesterday; his coloring is mostly back. I'm afraid to change his water tonight.
Okay, what you could do is skip the salt. Proper water changes should battle off any fin rot... however, get your water tested for PH, and hardness, and even metals. Some metals, and hardness and PH levels can cause burns and damage similar to ammonia and fin rot damage. Just in case
When I change water on stressed out fish, I use an airline tube and suck out 90% (leave just enough to cover them) and then put it back the same way. Much more peaceful since there is little change and current :)
But I'm out, things are getting too bizzare and confusing in here :)
It IS cute isn't it? Shiloh likes to chase fingers. He can only half flare, as a rescue he took some damage before I got him, to his face, sides, gill plates, and fins. I had to put him in a 20 gallon to stop his tail-biting