Sorry, but the type of fish you choose may determine whether a 12g is acceptable or not. Types abc may be fine together but types def may not work. Usually when someone asks a newbie question like how many fish can I put in a tank, it shows a lack of understanding on this point.Crush said:In regards to being more specific, I wasn't asking about the types of fish but was wondering if the amount (3) would be too much bioload for a 12g?