Fish atlas

This species is native to the tropical regions of the Western and Central Pacific Ocean. Its distribution ranges from the coastal waters of Palau to Tuamotu and the Marshall Islands. It primarily inhabits seaward reef slopes, current-swept drop-offs, and reef crests at depths between 4 and 30 meters, where the waters are crystal clear and rich in planktonic food carried by ocean currents.

Belonging to the family Serranidae and the subfamily Anthiadinae, Pseudanthias bartlettorum features a slender, elongated body that is moderately compressed. It has a relatively large terminal mouth. Adults reach a maximum total length of approximately 9 centimeters. The caudal fin is deeply forked, enabling rapid and agile swimming against strong reef currents.

This is a highly gregarious species that forms large schools consisting of hundreds of individuals in the wild. The social structure is highly organized and haremic, with a single dominant male ruling over a group of females. In captivity, they must be kept in groups of at least 5-6 individuals (one male and multiple females) to reduce stress.

It boasts a spectacular bicolored pattern: the back and dorsal fin are bright lemon-yellow, while the flanks and lower body are pinkish-violet. Mature males display more intense coloration, a more developed dorsal fin with reddish or violet filaments, and yellow coloration extending onto the snout. Females are slightly smaller and less vibrant.

To house a small group, a mature marine aquarium of at least 350 liters is required. The tank should feature a robust live rock structure with plenty of overhangs, caves, and crevices for shelter, while leaving a large open space for swimming. Powerful water movement and high oxygenation are essential to replicate their natural habitat.

A specialized zooplanktivore that requires multiple feedings per day (at least 2-3 times) due to its high metabolic rate. Offer a varied diet of high-quality frozen foods such as mysis shrimp, brine shrimp, copepods, lobster eggs, and finely chopped krill. Over time, it will accept small-sized vitamin-enriched pellets and flakes.

Requires clean, stable marine water parameters: temperature between 23°C and 26°C, pH range from 8.1 to 8.4, specific gravity (SG) from 1.020 to 1.025, and carbonate hardness (KH) of 8 to 12 dKH. An efficient protein skimmer and regular water changes are necessary to prevent nutrient accumulation from frequent feedings.

Completely reef safe and an excellent addition to mixed reef aquariums. It coexists peacefully with other non-aggressive marine fish like tangs, wrasses, and gobies. Avoid keeping more than one male per aquarium, as they will fight to the death. Do not house with large, predatory, or overly aggressive tankmates.

Captive breeding in home aquariums is extremely difficult. They are protogynous hermaphrodites: if the dominant male dies, the largest and strongest female in the group will change sex to become the new male. Spawning is pelagic, and rearing the larvae is nearly impossible in closed systems due to their microscopic size.

Due to their high metabolism, starvation is a major threat, and they can waste away quickly if not fed regularly. They are moderately susceptible to common parasites such as Cryptocaryon irritans (marine ich) when stressed by poor acclimation or temperature fluctuations. A quiet quarantine period is highly recommended.