Re: Siamese fighter in a bowl
#2
A temperature of 19/20 degrees is going to stress a Siamese Fighter, so adding medication won't do much good at this temperature - I would put him back into the main tank and treat him there, personally, as I've treated tanks containing Black Ghosts with Myxazin on several occasions without any problems, and they are my favourite fish, so I wouldn't take any chances! Protozin is the medication which can cause problems with knife fish if memory serves me right.
Be very careful not to overdose, however, because Ghosties are sensitive fish as you rightly say, and lots of other factors can influence their ability to cope with medications, for instance toxin levels, pH, hardness and overbearing tankmates can all contribute to the general stress level of the fish. As long as your water conditions are fine, and you stick to the dosage, you shouldn't have any problems - good luck!