Fish are hard to treat and a big part of it is cause we just don't even know what's wrong with them. I hope your guy makes it, but sometimes there's just not much you can do or you do everything possible and they still die. I have a betta who's been under the weather for months - fin rot (or maybe biting himself since for months now there's no actual evidence of rot other than some clean chunks missing), clamped, more lethargic than he used to be. I dunno wth is wrong with him. Tried antibiotics, a bit of salt, extra water changes, frozen foods. He's not dying but he's not well either and I dunno what else to do. Anyhow I got off on a tangent there - sorry. Point is that I agree it's very frustrating.