News / Feature Articles / Friendly, Lovable Damselfishes (11/19/18)

Friendly, Lovable Damselfishes

Friendly, Lovable Damselfishes
No family of coral reef fishes is quite so maligned among aquarists as the pomacentrids the damselfishes. The name alone sends a shiver down the spine of many, but theres often little justification for this piscine bigotry.

The behavioral problems associated with this group often comes down to a lack of research on the part of aquarists or poor advice from retail stores. Many a neophytic reefkeeper has been given the dubious advice of starting their new tank with a hearty Blue Devil (Chrysiptera cyanea) or Humbug (Dascyllus aruanus), but this is a surefire way to create an untenable situation when subsequent fishes are introduced.

Its important to realize that the Pomacentridae is an ecologically and behaviorally diverse group, more so than most reef fish families. There are a few bad apples, for sure, but these tend to be concentrated in groups that feed heavily on algae. Their bellicose nature is an adaptation that allows these small fishes to punch above their weight, enabling them to chase away the many competing herbivores that abound in coral reef ecosystems. In several of the most aggressive damselfish genera, like Neoglyphidodon and Microspathodon, colorful juveniles make for a tempting impulse purchase, only to quickly grow into adults that are mostly black in color and spirit.

But there are just as many, if not more, pomacentrid subgroups that are mostly harmless in aquariums. These tend to be species that feed heavily on zooplankton, where theres less need for aggression. This herbivore versus zooplanktivore dichotomy isnt entirely foolproofDascyllus are a semi-aggressive example of the latter, while the Yellow-tail Damselfish is a fairly docile instance of the formerbut, on the whole, this rule of thumb can be helpful in understanding the behavioral diversity within this heterogenous family. That being said, lets meet some of the more peaceful options available to aquarists.

Green Chromis (Chromis viridis)
Along with the Lyretail Anthias, there are few reef fishes quite so abundant and ubiquitous throughout the Indo-Pacific as the Green Chromis. It seems that just about any photograph taken of a shallow reef will feature a shoal of this species, often hovering just above colonies of branching Acropora. The interstices of these corals function as an important refuge for these vulnerable little fishes, and specimens in aquariums will readily replicate this behavior when approached.

The sublime shade of blue-green seen in Chromis viridis has few equals among reef fishes, though the Black-axil Chromis (C. atripectoralis) is a close cousin that could easily be confused. Its important to keep these two lookalikes separate, as they can be quarrelsome with each other, so keep an eye out for the small black patch hidden behind the pectoral fin in C. atripectoralis. That species is another fine option, though its larger size lends it a bit more of a boisterous personality relative to the Green Chromis. Both species should be kept in as large a group as possible, and, for C. viridis, its not unheard of for males to develop their gorgeous breeding colors in captivity. This can vary from a mostly yellow body, to specimens that darken their dorsal and pectoral fins.

Sapphire Damselfish (Chrysiptera springeri)
Chrysiptera is a difficult group to summarize, as there are some species that are highly territorial and very mean-spirited, while others tend more towards the innocuous. Theres actually an easy explanation for this... the genus has long been known to be made up of several disparate lineages and will eventually be split into separate genera. For instance, the meanest of the lot, C. brownriggi and C. unimaculata, represent a very distinct group, while one of the most placid, C. kuiteri, is an apparent close relation to the rarely seen Amblypomacentrus.

The species considered to be the true Chrysiptera are those that are most closely related to the Blue Devil (C. cyanea), which is itself a notoriously untrustworthy fellow. This reputation is not entirely unearned, but much of its aggressive tendencies come down to which species it is paired with and in how large of an aquarium. For a safer bet, try the similar Sapphire or Springers Damselfish (C. springeri) or its undescribed sister species from the Philippines. In addition to its good looks, this fish has a penchant for dining upon pestiferous flatworms.

Fusilier Damselfish (Lepidozygus tapeinosoma)
Imagine a damselfish that thinks its an anthias and youll have a good idea of what Lepidozygus is all about. The Fusilier Damselfish is named after its overall similarity to fishes in the family Caesionidae, known commonly as fusiliers, though the resemblance is only superficial in this instance. Both are adapted for a streamlined life hovering above the reef, plucking at passing zooplankton.

With a maximum size of just over 4 inches, Lepidozygus is roughly the same size, shape, and color as various Pseudanthias species, and they often can be found swimming alongside them in mixed-species shoals along reef drop-offs. Aquarium specimens require the same sort of care as would be given an anthias, with regular feedings throughout the day being ideal.

Ocellaris Clownfish (Amphiprion ocellaris)
Many aquarists are entirely unaware that anemonefishes and clownfishes are simply a specialized subgroup of the Pomacentridae. This shouldnt be much of a surprise, really, as they are in their own way fairly pugnacious, though this aggression tends to be limited to the area directly surrounding their host anemone.

Pound for pound, Amphiprion and Premnas can certainly among the most belligerent of aquarium fishes, often biting the literal hand that feeds them. This is especially true of larger species, like the Tomato Clowns, the Maroon Clown, and the Clarks Clown. To an extent, this can be mitigated by not keeping them alongside their anemone host (though wheres the fun in that). For a more peaceful option, theres always Nemo, AKA Amphiprion ocellaris, as well as its sister species A. percula. This pair of orange and white striped bois grow to around 3 inches in length and are only modestly bitey, though its still quite normal for them to chase other fishes away when called for. But, compared to the murderous intentions of some damselfishes, these smaller clownfishes are fairly benign.

Golden Damselfish (Amblyglyphidodon aureus)
Arguably the best combination of size, color, and peaceful demeanor to be found among the pomacentrids occurs in the sensational Golden Damselfish. The genus Amblyglyphidodon is home to 11 species, several of which find their way into the aquarium trade on occasion, and they just might be the best kept secret in reef fishes. The largest and brightest of these is A. aureus, which can reach around 5 inches in length. But despite this large size, this species rarely causes any trouble in captivity, either towards fish or corals.

For a rarer option, theres Tongas endemic A. melanopterus. It features a body similar in color to the Green Chromis, but with blackened fins posteriorly. Any of the members of this genus can be kept either singly or in groups, and breeding has been reported in captivity, with eggs laid in available crevices. All of the fishes discussed here will thrive on a mixed diet of dry and frozen foods, and all are relatively hearty and disease resistant. So enough with all the pomacentrid misconceptions... there really are a lot of friendly, lovable damselfishes out there.