Flitting in and out of the rockwork, squabbling among themselves and charming viewers with their plucky personalities, what marine aquarium is complete without damselfish?

What they lack in size, they make up for in color and boldness. Long regarded as starter fish, they’re usually the first finned denizens to be plopped into a newly-set-up tank. Because of their toughness (and probably because they’re the cheapest of all marine fish), they’re usually employed to “cycle” a new tank, jumpstarting the nitrogen cycle and almost always surviving the subsequent spikes in ammonia, nitrites, and nitrates which would turn most other fish belly up.

Blue Devils (Chrysiptera cyanea) are the first fish of many marine hobbyists. Extremely brightly-hued and inexpensive, they can survive for many years in aquaria without losing their eye-popping coloration. As with all damsels though, they’re always spoiling for a fight. (Coral Triangle Adventures)

Diverse damselfish

Among our most common and familiar damsels are the 30 species of clownfish (which we’ll discuss in a future entry), plus blue damsels, green chromis, yellowtail damsels, sergeant majors, striped damsels, and dominos. Many species look similar enough that referring for instance to “blue damsels” can mean dozens of predominantly blue or bluish species.

Except for the Atlantic Garibaldi (Hypsypops rubicundus) which can grow to 12 inches, as most damsels grow no larger than three inches. In shape and habits, they’re like the familiar freshwater cichlids. Most have forked tails, two anal spines, plus a single nostril on each side. To many people, they resemble smaller and more colourful tilapia.

Most damsels are what are called demersal or bottom-hugging fish, lording over a patch of coral or rock, grazing on algae, or hunting for tasty invertebrates skulking in crevices. Species like the Blue Green Chromis (Chromis viridis) form large shoals above corals and snap up drifting plankton. The rarest species like the Freshwater Demoiselle (Neopomacentrus taeniurus) can even survive in full freshwater!

Black Velvet Damselfish (Neoglyphidodon oxyodon) are the author’s favourite and quite possibly the most colourful of all damselfish species. Extremely attractive when young, these fish however, turn grey when they mature – a process that can take over a decade in a well-tended tank. (Pet Solutions)

Damsels in distress?

Pretty as they are, damsels are rarely given a second look by divers, often eclipsed in the wild by larger and more uniquely-patterned fish like angelfish, butterflyfish and triggerfish. Though especially colourful when young, some also literally turn old and grey after a few years, even in the wild.

But the Best Alternatives Campaign, a movement which promotes more sustainable practices for the aquarium trade, thinks it’s finally time to give these little jewels their proper due. Aside from their bright colors and cool behavior, damselfish are some of the hardiest of all marine fish, surviving conditions and innocent mistakes that less experienced hobbyists will inevitably run into.

Best Alternatives estimates that 90% of all tropical marine fish caught for marine aquaria die within a year of capture, mostly because of the continued use of illegal cyanide. Add poor packing, shipping, transportation and holding practices and up to 80% of wild-caught fish will have died before they’re even obtained by hobbyists.

Those that do make it into tanks face another series of adjustments – new water conditions, temperature fluctuations, tank mates, and diets. Disease outbreaks in smaller tanks are also far deadlier than in the open sea. Because of all these factors, captive marine fish that survive beyond a year are those who are taken care of properly – or tough as nails to begin with.

Well, there are no tougher marine fish than damsels, which is why they’re really the way to go not just to drive hobby costs down, but to curb the marine aquarium trade’s alarming mortality rates.

Did you know?

There are currently 385 recognized damselfish species, belonging to 29 genera spread mostly throughout the Indian and Pacific Oceans. New species are still being discovered each year, with three found in the Philippines in 2019, according to a 2019 article by Mikael Angelo Francisco for FlipScience.ph.

Three-stripe Damsels (Dascyllus aruanus) are familiar because they’re one of the fish featured in the movie Finding Nemo. In the wild, they aggregate in groups of several dozen with lookalike species like two-stripe and four-stripe damsels, which they can also coexist with in captivity. (Vivid Aquariums)

Damsel care

Just because they’re tough doesn’t mean you shouldn’t provide the best living conditions for these little jewels. Provide plenty of rockwork, particularly artificial coral reef modules made of resin or concrete (no live coral please). Damsels absolutely relish cover so the more hiding places, the more individuals and species you can mix in a tank.

Tankmates should be equally hardy, like clownfish, cardinals, wrasses, surgeonfish, gobies, blennies, dottybacks, or, best of all, other damsels. Avoid deadly beauties and bullies like lionfish, groupers, snappers, and anything large enough to turn your pets into damsels in distress.

Feeding won’t be a problem as damsels will greedily gobble up everything from el-cheapo flakes to high-grade pellets and haplessly floating brine shrimp. Water temperature should be kept between 73°F to 82°F while pH levels should range from 8.1 to 8.4 with a specific gravity of 1.020 to 1.024.

Fun to watch, easy to keep, and brave enough to bite aquarists’ hands (don’t worry, their bites just tickle), damsels will always be among the best fish for your marine aquarium.

Feisty fish

Without enough cover and space, damsels will quickly turn into tiny attack machines, chasing and nipping the fins of more docile fish like batfish or butterflyfish. Like keeping Malawi cichlids, use at least a 30-gallon tank and keep either one of each species or groups of at least six of each, which helps spread out aggression while maximizing visual impact.

This appeared in Animal Scene magazine’s May-June 2020 issue.

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