ur NO3 is too high for these fishes...try to reduce ur NO3 n have ur perimeters stable. as long as the fish is stress free, it will not fall sick easily. at the mean time, dose more bacteria. i used to think how bacteria can help fishes to be healthy. but after i start dosing them, fishes become more lively and do not get ich often. add the rest of the fishes that u wan b4 adding the AT or PBT. right now i cant add anymore fishes due to my PBT, no matter what fish, wrasse, angel....sure kena whacked jialet jialet by the PBT.