The Samoan Cardinalfish Nectamia savayensis is also known as the Fo Cardinalfish. They are not commonly seen fish because of their nocturnal habits and to date have only been seen in Tanzanian waters on the wreck of the Slemmestad at night at around 8 meters. This location has large deep crevices and cave like areas which provide good hiding places that are inaccessible to divers. It is also surrounded by rubble.
At first glance they are easily confused with the Ghost Cardinalfish seen below . Unless one can get a close up view they are not easy to distinguish except by their behavior.
The body is a silver colour with light black vertical bars running down the body. In the caudal area there is a black bar above the lateral line. On the leading edge of both dorsal fins there are black lines present. Under the eye there is a wedge shaped mark at a 45 degree angle. They grow up to 8cm in length.
SAMOAN CARDINALFISH IN THE WILD
The Samoan Cardinalfish are nocturnal feeders and during the day hide in crevices or deep caves. At night they come out to feed and form small shoals of ten to twelve fish or less. They are quick to dart back into cover. The shoals swim a few meters above the bottom against the side of the wreck. The Ghost Cardinalfish we have seen have all been singular and have hugged the substrate.
The Samoan Cardinalfish is found across the Indian ocean and in the West Pacific up to Southern Japan and down to Australia. They have been found between depths of 6 to 8 meters in Tanzanian waters to date.
The Samoan Cardinalfish are nocturnal feeders , feeding mainly on zooplankton and small benthic organisms.
With all Cardinalfish, during breeding pairs are formed and after performing a mating dance, the eggs are laid by the female and fertilized by the male. The male then collects the fertilized eggs and carries the eggs in his mouth until they hatch. During this time the male cannot feed. Towards the end of the incubation period the males become quite skinny making the protruding mouth more noticeable. This can result in cannibalism with the male eating some of the eggs. We have only witnessed the egg laying on one occasion and it seems to occur on nights with a full moon.
Samoan Cardinalfish are probably not commonly kept in aquariums being one of the lesser known species. Some cardinalfish have been bred in captivity by breeders such as Orafarm where they are occasionally available.
Purchasing captive bred fish takes the pressure off of wild populations and if one can do so one should. Most Cardinalfish are reasonably hardy and easy to keep.
SAMOAN CARDINALFISH CLASSIFICATION
Species: A. semiornatus
Bray, D.J. 2016, Nectamia savayensis in Fishes of Australia, accessed 16 Feb 2018, http://fishesofaustralia.net.au/home/species/2158