The Bad
The short answer to the question, “Do Damsel Fish Deserve Their Bad Reputation?” is, “yes, yes they do.” But the long answer is “well, most do, but certainly not all.” That’s right, there are species of damsel fish that you can keep without risking life and fin of all your other fish. Damsel fish are aggressive and armed with a strong bite and dental plate that can do some pretty serious damage. When they are small this might not kill the other fish but the constant attacking will. A damsel can be relentless and that means the other fish under attack has no chance to rest and is stressed out. Stress, if I haven’t stressed it enough, is a fish killer.
The Ugly
The other issue with damsel fish is that most of them are a bit of a scam.
How can a fish be a scam? The two photos below will show you what I mean.
This is the domino or three spot damsel (dascyllus trimaculatus). It’s it cute!
The below photo is the same fish as an adult. It’s 6 inches long and deep keeled. It’s a beast and the older it gets the more aggressive it gets. You think you are getting some cute little black fish with spots but you end up with a giant meaty fish that is brown or gray and rather common looking.
The Good
But not all damsels are evil. There are a group that stay small and attractive. They are still relatively aggressive but mostly among their own kind.
The yellow tail blue damsel is one of my favorites. They get aggressive with each other so they need enough room. Once they escape they are allowed to escape. Domino damsel will keep after another fish even when it wants to hide.
Some damsel are being captive bred now which will mean they are extra hardy. They are already good beginner fish in terms of how hardy they are and the fact that they readily eat flake. Their only drawback comes with those that change when adults.
I have mentioned the yellow tail blue damsel but there are other species that I recommend as well.
Azure damsels, yellow tail blue (see video above), Allen’s, Gold belly, Caerulean, neon, lemon, Springer’s and pavo are all peaceful species of damsel.
I don’t want to condemn the entire group because of a few bad apples (three spot, blue devil, ambon, and blue back to name a few).
If you are just starting out in marine fishkeeping I recommend the hardy damsel to you. Even the large and aggressive ones can be kept if you put them in the right environment. For beginners though I recommend the above smaller and less aggressive fish.
Source: Biota Introduces Captive-Bred Sapphire Damsels