it needs full brackish conditions to survive this is probally why it looks so bad so please dont make this worse on them and put them in with your discus
well the owner of the fish store is an idiot he knew nothing about this fish.
Thanks for letting me know its a bad idea to buy him.....i was really tempted
not a bad idea to buy him a bad idea to not put them in a full brackish setup get them setup a brackish tank there are some sweet brackish fish that can go with them like archers
As others have mentioned, they're truly a brackish water species that prefers water parameters that are totally incompatible with your discus' requirements. While discus generally prefer soft acidic water, monos do much better in hard alkaline water with a generous amount of salt added. I've kept both species of monos, M. argenteus and M. sebae. IME, they definitely do better when kept in 1.005 SG to 1.015 SG conditions. In fact, M. argenteus is often kept in SW aquaria.
BTW, this thread should be in the Saltwater & Brackish forum, as monos aren't cichlids.