|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, Royal Blue Damselfish may be found in small groups within sheltered lagoons and inshore reefs, usually amongst Acropora spp. 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. The Royal Blue Damselfish is capable of dramatic colour change from blue to completely black when stressed - this is thought to help the fish avoid predation. May also be seen on sale as the Blue Sapphire Damselfish or Springer's Demoiselle.
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 is being bred on a small-scale commercial basis. In the wild, these fish are known to form distinct pairs 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.