150 gallon

150 yellow tail damsels :).

If I was going aggressive with a tank that size it will have to include a clown trigger as the centerpiece. Assume this will not be a reef?
 
More info, looking for just a couple fish or several? How active? How much precaution do you want to have to take to stick your hand in?
 
If you want alot of colorful aggressive fish (talking fw here) african cichlids are the only thing that come to mind that fit that

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Harem of anthias (or a couple of harems)
Pair of flame hawkfish
Handful of watchmen type gobies and matching pistol shrimp
Couple/few small to medium sized angels and/or wrasse

You will have movement everywhere and all levels.
 
This is in the marine forum, so unless specified otherwise, as Austin did when talking about cichlids, recommendations will be marine fish, not fresh or brackish.
 
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