I'm thinking of getting a few gold fishes in to my 55 gallon tank. I have had an oscar for 4 years in there, it grew to 12 inches and 4 days ago it jumped out. My water: Ph-7.5, Kh- 4 and temp. 80F,(NitrAte-10 NitrIte-0) is this ok? How many fish can I put in to the tank concidering their adult size of 12 inches and their waste output? Once again since I had an oscar, do yoou think bacteria will be able to handle ammount of waste from lets say 3 adult goldfish? Thank you in advence.