|Maximum Size||5.5cm (2.2")|
|Sexual Dimorphism||Very difficult to distinguish. Males in breeding dress may appear an overall brighter colouration compared to the females. However, this is not a given.|
|Temperature||Tropical: 23-27 deg C (73-81 deg F)|
|Water Parameters||SG: 1.020-1.025, pH: 8.1-8.4|
|Lighting||No special requirements|
|Reef Aquarium Compatibility||Excellent|
In the wild, Emperor Damselfish may be found in small groups within bays and sheltered fringing reefs, usually amongst Acropora spp. and Seriatopora hystrix corals, feeding mainly on zooplankton in the water column. Although these pretty fish are considered much less aggressive than many of the damselfish species, their assertiveness often increases with age and maturity. It is therefore advisable to keep either a single specimen, a known male-female pair, or a large sized odd-numbered shoal (9+) introduced simultaneously as juveniles into a spacious tank with plenty of hiding places amongst the rockwork. Smaller groups are often known to suffer fatalities. Choose tankmates with care, avoiding any really docile species such as firefish and cardinalfish. This vibrant species was formally described in 2010, with the fish previously being known as Chrysiptera cf. parasema in reference to the close resemblance to the Yellow Tail Blue Damselfish (C. parasema). C. arnazae may be told apart from C. parasema as the former not only has yellow on the caudal fin and caudal peduncle, but it also displays yellow on the posterior margins of the anal, dorsal, and pelvic fins.
Offer a varied diet consisting of small frozen foods such as Spirulina-enriched brineshrimp, Mysis shrimp and finely chopped krill, plus marine flake food and herbivore rations. Feed small amounts 3 times per day.
This species has not been bred in the home aquarium, but they are known to form distinct pairs in the wild when spawning. Male damselfish typically establish a territory and prepare surfaces of rubble or coral for females to deposit their adhesive, demersal eggs. Once the eggs are laid the male will quickly fertilize them and aggressively defend them from any intruders. He will also aerate the eggs until they hatch.