News / Species Spotlight / Species Spotlight - Similar Damselfish (Pomacentrus similis) (11/08/17)

Species Spotlight - Similar Damselfish (Pomacentrus similis)

Species Spotlight - Similar Damselfish (Pomacentrus similis)
With its blue body and yellow caudal fin, it would be easy to mistake the Similar Damselfish for the ubiquitous Yellowtail Damselfish (Chrysiptera parasema). The two, however, are only distant relatives and can be told apart by the differences in their body shape, fin morphology and the details of their color patterns. For instance, the yellow fin of P. similis is bordered along the edge in blue, and in C. parasema it fades to clear.

Instead, P. similis belongs to a group of highly similar species (P. coelestis, P. caeruleus, P. micronesicus, P. auriventris, P. alleni) which share a common motif of a shiny blue body and yellow fins. Many of these find their way into the aquarium trade, with the Blue & Gold Damselfish being arguably the most commonly seen and most popular member. On the other hand, P. similis is fairly uncommon, though exports do appear semi-regularly out of Sri Lanka.

Aside from Sri Lanka, the rest of the known distribution for this fish is in the Andaman Sea, though it likely stretches further south along Sumatra and Java. Here, it occurs alongside the closely related P. alleni, but the two can be told apart easily based on the coloration of tail. The closest relative (i.e. the most similar) is probably the Neon Blue Damselfish (P. coelestis), which occurs across the West Pacific and differs mostly in the relative amount of yellow along the belly and fins.

All of these Pomacentrus form large shoals that hover high above the substrate to feed on zooplankton. For this reason, these are generally less aggressive than what we see in the more strictly benthic species that browse upon algae. In an aquarium, a small to large group is strongly recommended, though single specimens will generally fare fine in smaller tanks with docile tankmates. Most any food will be accepted, but frozen crustaceans will most closely replicate the natural diet. And, of course, these are perfectly reef safe!