Chromis nigrura – Blacktail Chromis
Chromis nigrura was officially described in 1960 by South African ichthyologist Smith. Their common name is Blacktail Chromis.
The genus name Chromis is derived from ancient Greek and means Fish or Perch.
This species belongs to the family Pomacentridae. This family has about 29 genera and 285 species. The genus Chromis comprises nearly 100 species, making it the largest genus within the family. The Pomacentridae family includes the Clownfish and Damselfish.
Chromis nigrura is a very beautiful little Damsel. They grow up to about six centimetres long. The top and bottom of the fish are light blue which fades to yellow on the flank. On this yellow, they show a few rows of blue dots. The dorsal fin has a yellow band. The anal fin is deep blue, almost black. The caudal fin is trimmed at the bottom and top with a black band.
This species is very similar to Chromis vanderbilti and Chromis lineata. Only the tail is different, Chromis nigrura has two black bands on the top and bottom of the caudal fin. In Chromis vanderbilti the top edge is yellow, this species also has a very small gold dot under the rear part of the dorsal fin.
The habitat of the Blacktail Chromis includes the Indian Ocean. They are common along the east coast of Africa to Sri Lanka and the Maldives. They can also be found around the Cocos Islands and Christmas Island. They usually occur in schools of 10 to 15 copies. Larger schools up to 30 pieces are less common.
Chromis nigrura is usually found in schools above reefs at depths of two to thirty meters. They always ensure that they remain reasonably close to the reef so that they can withdraw between the coral or rocks in the event of imminent danger.
In the wild, Chromis nigrura feeds on Zooplankton with a preference for copepods. Zooplankton is common above the reef. Small amounts of algae are also eaten.
In the aquarium, you can feed them with copepods, brine shrimp, small or finely chopped food such as Mysis, fish meat, shrimp, mussels, cyclops etc. You can also give them flakes. In any case, make sure they also get some vegetable food. Think of omnivorous or herbivorous flakes or spirulina flakes.
The Blacktail Chromis is a real schooling fish and should, therefore, be kept in a group. Think of at least a group of five, but more is better. If the fish are kept in too small a group, they cannot divide their attention and aggression. This often results in the death of the weakest in the group, until only one remains. They usually leave other species completely alone. This species does not grow very large so be careful not to combine them with oversized species that eat fish.
A group of five can be kept in an aquarium from 250 litres. They need a reef between which they can shelter in case of danger. However, they swim above and in front of the reef during the day, so plenty of open swimming space is definitely needed.
It is a hardy species that is also suitable for beginners. In the reef aquarium, they leave corals and invertebrates completely alone. So they are reef-safe!
Beware! Chromis nigrura is a somewhat shy species that is easily startled. Often they shoot towards the reef or coral to take shelter. However, they can also jump above the water. Make sure that the aquarium is well covered with a lid or net.
Breeding Chromis nigrura
As far as I have found, Chromis nigrura is not bred in captivity.
They form a couple to spawn. For this they perform a mating dance in which they attract each other with quick movements. The male darkens a bit during this period. The eggs are deposited at sunset.
The eggs are glued to a clean piece of rock. The eggs are guarded and fanned by the male. After the young fish hatch, they have to take care of themselves.