i want to buy a discus buy want to know if any of you owners out there have discus that live with other fish. right now i have 2 angels, 4 tigers, 1 black ghost, 2 tetras, 1 serverum, 1 pictus catfish, and 3 algae eaters. can they live with these guys in peace. also how many water changes do i have to do a month? thanks for the help.