I'm trying to start a Discus tank and wouldn't ya know, I go to PetCo and some guy dropped off a 5in Discus that is black as night. He also dropped off a Leaf Fish and two Puffers. What do I do??? I wasn't ready for the Discus. I was about to order from Great Lakes when this happened. I can't let this guy die... the store gave him to me for free. I have a 10 gallon quar tank and an RO/DI filter. Somebody better help or this Discus is dead! Can I even save him????