If it was me , IMO ~ I would try to get rid of the weakest links' , as you are not too sure, def. get the right' advice, and dont belive everything your told. I would say to keep 6, maybye even 4 in that tank and they will get more air, and be able to hide better, e3sp when you add some wood, rock, plants ...... somthing they can run around and dash in and out of . that is what they love to do . I appluad you on your discus purchase, it takes experance to learn, and one day you could be a fine breeder. who knows, maybye even a pair or two from this batch ! just be careful . water changes are a must for these fish . am glad your working on a easier way ! and too much food is not good ethier . that only dirty's the tank . I know you want themn to eat , and poop well . but you dont want to get your tank so nasty . I would try to find someone local . ask your LFS if they know' of a breeder, you can act' like you want to buy, you might later ...... and look at his/her tanks. see thier fish , ask then if they would look at your fish . ask questions online as you are.... and find out if any are sick, or just worn & torn from the conditions they were in before. what size tank were these fish in ? sounds like there were far too many , for far too long . Be careful to not make the same mistake . they need room to grow. try to best as you can find the weakest ones, sell them off, or do what you can .... that way you will have more room in your tank for the healthy ones to grow stronger. BE REALLY careful with medicines !!!!!!! I cant stress this enough . !!!!!! ~~~~~ read, read, read. all you can before and after, and water changes will be your key . PleASE get some types of decor in that tank asap . so they can hide, run... play ~~ without being so aggresive, It is the beginning of this , wait till they get comfortable, when they are sure this is thier home for good, they will get worse with the fighting this is why you need the plants and other decor as hiding spots, and run around playground...... I too want some discus soon . I got me some angels for now . they are growing and doing well, havent found a pair yet, sure I will by summer as they get bigger . I would have ran to get these just as you did . So just watch these guys and good luck !!! ~
HTH and IMHO ~