I'm a member at other reef sites, but not here. I stumbled across this thread and registered just to post this. I agree that no fish is 'evil', damselfish just by nature are aggressive and that's how they protect themselves and survive in the wild. That being said and out of the way... Be very cautious adding this to your tank. If you add it, add it as the last fish. I added it to my 75g which also already contained 2 Ocellaris clowns, a yellow tang, coral beauty angelfish, and 3 chromis. For the most part it left everything alone, however the caudal fin of my coral beauty was completely nipped off by something... I'll get to that later. I'm completely rebuilding my 75g system, and while I do that, I temporarily have them in a 30g 'holding' tank. I added all of the 75g fish into the 30g at pretty much the same time. Well the 6yo ocellaris suddenly died a few days ago for no apparent reason, was 100% healthy and happy. Next day I go down to check on them, the 4yo ocellaris is in VERY bad shape, listless and just hanging on. Then I see what’s going on, the Jewel Damsel is attacking it, hardcore attacking it. I removed the damsel and put him in the Rubbermaid container holding my LR that wouldn’t fit into the 30g, but sadly the 2nd ocellaris didn’t make it. The next day, I find a 3rd dead fish, the angel. Since the entire tail was nipped off, it appeared to be infected a bit, but I’ve been shocked how quickly fins repaired themselves in the past so I let it go. Well I figure it succumbed to the infection finally, so I pin it’s death on the damsel as well. Meanwhile, it’s important to state that the entire time my yellow tank and chromis are healthy and happy. Because the clowns’ deaths were sudden after years of health, and the other fish are healthy, I can’t blame water params or disease. Catching the damsel red handed in the middle of an attack is all the evidence I need. So I don’t say all this to ‘prove anyone wrong’ or even to give my sob story. I’m just stating my experiences with the Jewel Damsel. While it was a seemingly peaceful member of the community in the 75g, I wondered why damsels got such a bad rap. Then in the 30g, it’s suddenly a murderer. YMMV, just be sure to use discretion with fellow tankmates, add the damsel after all others, and give it enough space to satisfy its territorial needs. Best regards, joel PS - I will concede that it is quite a stunning fish regardless of its behavior! Drab brown body, but speckled with the most beautiful blue dots.