depends really though I would only keep a pair personally with some dither fish and the two cats =p
posting tank specs helps as some people ask the same thing and then later they say their filtration is rather small. I'd be more worried about filtration and how much divided territory you can give, using landmarks of sort, like plants, rocks or wood. also frequency of water changes would have been helpful, for the most part I believe most people on this site are fish lovers like myself and don't really like answering the question "how many can i fit in this" as that is a terrible, almost like "how many can I squeeze in to this tank before they are no longer comfortable". My goal is to have my fish be as comfortable as I can possibly afford.