Some quotes from wet web media dot com.
Maroon Clownfishes can be, become outright MEAN... particularly if crowded, especially if placed with other fishes, clownfish species included, that will not "back down", recognize their obvious superiority. Some folks try to diminish this tendency to "rule all" in their Maroon tanks with the addition of anemones, more decor... this almost NEVER works.
Of all Clownfish species, Maroons are likely the very most changeable, flexible in their behavior, but also the downright orneriest as well. They can easily take on even larger triggerfishes, puffers, basses... and tear up hexacorallian tankmates... corals and anemones especially. The key descriptor in their intelligent care is "keen observation"... You must keep your eye on them, lest they "go ballistic". It is highly recommended that you intentionally place your Maroon/s last or close to last as fish livestock AND that they be what you want as the "alpha" fish... Even in tanks of a few hundred gallons.
This fish gets big... nearly seven inches long in the wild, just slightly smaller in captivity, and can be, to put it mildly, feisty with its own kind and other livestock. I would not place a single individual in anything smaller than a forty gallon, or two in a sixty
So... you can read this off like a checklist: Do you have a large enough tank (forty gallon for one, sixty for two minimum), that can use a "boss" fish? That you might have its hexacorallian organisms shredded? Lots of time to wait on a beautiful fish or two? Well, you just might be a candidate for Maroon keeping. Most problems with this fish are self-generated... people trying to keep them in too small a system, not as the alpha fish, buying large wild-caught specimens and not properly quarantining them... Avoid these common mistakes.