I came across two turquoise discus the other day for a great price so I took them home with me. After closer inspection once home, I notice the smaller one (about 2.5-3 in) was very skinny, with a concave forehead. The other looks to be much more full looking. Both act fine but will not eat flake food, only frozen brine/mysis shrimp and bloodworms. Does this sound most likely like an internal parasite? I have prazipro so should I dose the whole tank? I do not have a QT tank. Id like to hear your opinions as soon as possible so I can treat these guys and get them as healthy as they should be!