Domino Damsel

The Domino Damsel is one of the most recognizable damselfish species, named for its bold coloration pattern of a jet-black body adorned with three prominent white spots, one centered on each side and one on the forehead, reminiscent of a domino game piece. Juveniles display this striking pattern most vividly and are frequently associated with large sea anemones in the wild, where they shelter among the tentacles much like clownfish. As adults mature and reach their full size of around 5 inches, the white spots may fade and the fish becomes an imposing, uniformly dark territory holder.

In nature, Dascyllus trimaculatus is found across an enormous range spanning the entire Indo-Pacific, from the Red Sea to Hawaii. Juveniles commonly shelter in the tentacles of large carpet and magnificent anemones, gaining protection from predators. As they grow, they transition to living among branching corals and rocky outcrops, becoming highly territorial. They feed on zooplankton, algae, and small benthic invertebrates, and are extremely adaptable to varying reef conditions.

The Domino Damsel is among the hardiest marine fish available, tolerating a wide range of water conditions and readily accepting any food offered. However, its extreme territorial aggression as an adult is its major drawback. A fully grown Domino Damsel will fearlessly attack fish many times its size and can single-handedly terrorize an entire community tank. For this reason, it is best kept in larger aquariums of 55 gallons or more, with robust tankmates that can withstand its bullying. Despite these behavioral challenges, the species is reef-safe and will not harm corals or sessile invertebrates.