I'll answer with respect to the wrasses. I have a 220 gallon tank and currently have three different types of wrasses in the tank - a dusky, a mystery and a tamarin, all three of which get along well together. I believe you can have quite a few different wrasses but generally no two of the same kind. Also, not all wrasses are alike. Some are more aggressive than others. I think it helps if you have wrasses of different sizes as they are less likely to feel challenged.
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