A: I take half of the water for the bath from the main tank and the rest is fresh new water so about 3 1/2g of both.
TBTB: Sounds like it should be fully aerated... but who knows. Maybe it was better safe than sorry. But if I had to guess, I'd think it almost died from the high dose of PraziPro. If not mistaken, it should come as a solution/suspension in some kind of organic solvent that mixes with water, like an alcohol or a glycol because praziquantel itself does not dissolve in water and it is not easy to even suspend it in water. So, not only you added a lot of med, you also added a lot of that solvent with it, actually likely 100-1000 times more of it in quantity than the med itself. The solvent also has a dose, including a lethal one. Everything can be a toxin and poison - it's just a matter of the dose... as the common wisdom goes. If a human drinks 5 gallons of water, it will kill him/her.
A: Looking at the catfish this morning, it actually looks like the wounds are healing so I think I'll do one more bath tomorrow, then a water change since on the melafix, it states to medicate the fish for 7 days, then do a water change and if the fish still continue to look sick, to continue medicating. Since the catfish appears to be healing, should I stop with the melafix or should I continue doing it until he is completely healed?
TBTB: I'd follow the instructions on the bottle. If the instructions don't state otherwise, I'd continue treating until fully healed and then perhaps for another week after. Melafix, when applied properly, is a very mild and actually natural anticeptic (an extract from a plant). It is very safe and hard to overdose too.
