De-worming and Discus bloat

Hi there. I'm sorry that you haven't had any replies yet, hopefully a more knowledgeable discus keeper will come along, however I have kept them before and I know a little bit. First off, that tank is way too small for discus, even if temporary. I think that anyone who knows about them will tell you this. You most likely know that they are very sensitive fish, and even if your water parameters are prefect on paper, they could be easily stressed from being kept in that small of a tank, leading to all kinds of problems. I once had a pair in a 200L, and as they grew, that tank just became way too small for them really. You will hear different advice from different people, but I often hear that 200L is the absolute minimum to have one/two discus, however just going by past experience, I wouldn't keep any in anything less than 300L, ideally 350L and up. They really do need lots of open space to swim, and one of mine grew to over 16cm.

I think that before anyone can answer your questions, you need to post your water parameters, especially water temp, GH, PH, nitrate, etc. Is that tank bare, or does it have substrate/gravel? How often are you doing water changes, and how much water? Are there any other fish in with them? If some of them are only 9cm then they fully grown yet, so they are either much younger than the larger ones, or they are stunted (which will happen if they are kept in that small a tank). Did you get them all at the same time, and where did you get them from (breeder, shop, etc.)? Are they all eating, and what and how much are you feeding them? This may seem like a lot of questions, but it's all very important to know before anyone can help you diagnose anything with your fish.