I am currently running a freshwater Cichlid tank (90 gallon) with oscars and blood parrot and Im planning to change my setup to Discus tank. What are some tank mates a discus can have? (blood parrot or black convict is possible or not?) What does the PH level would need to be at? How many Discus fish can I have in my 90 gallon tank? WHat are some recommended tank mates if the Discus fish are small baby size?