Spawning, embryonic development and larval culture of redhead dottyback Pseudochromis dilectus Lubbock, 1976 under captivity

Abstract

Reproductive behaviour, captive breeding, embryonic, larval development and suitable live feed for Pseudochromis dilectuswere found out. Fishes ranging in total length 80–120mm(male) and 70–80mm(female) were reared in FRP tank (1000-L) for six months to develop pairs. The pairs laid ball-shaped egg mass (25 to 35mmdiameter)which consisted of 400 to 500 spherical eggs/pair/spawning (n=18).The size of the individual egg varied between 1743 and 1919 μm and all the eggs were interconnected by fine sticky threads. The egg ball was white or transparent on the first and second day, black on 3rd day and silvery on 4th day of incubation. The hatching rate varied between 91 and 95%, and the peak hatching took place under complete darkness on completion of 96 h incubation. Total length of the newly hatched larvae varied between 5.1 and 5.3mmwithmouth gape 150 to 160 μm. First feeding started at 10 to 12 h after post hatch. The study concluded that Euplotes sp. (0 to 5 dph), enriched rotifer (6–15 dph) and microalgae enriched Diaphanosoma celebensis (16 to 30 dph) can be used as effective feed for high survival of larvae of P. dilectus. On 20 dph the metamorphosis initiated and became juvenile stage at 30 dph (82%). At 45 dph, all the larvae transformed to juvenile and shifted from pelagic to epibenthic in the aquarium with denser body having reddish colouration. Statement of relevance: Pseudochromis dilectus (Family: Pseudochromidae) is a species of keen interest in marine aquarium trade and has distribution in the Western and Central Indian Ocean to Sri Lanka. As its males are colourful than the female, males are selectively exploited fromthe nature for aquariumtrade which is also causing threat to natural population thereby reducing its availability. Hence captive production is a potential solution for reducing pressure on the natural stocks. However no scientific studies were conducted in P. dilectus with an objective to captive breeding. Hence the present study was aimed to generate baseline information on its reproductive behaviour, spawning, egg morphology, embryonic and larval development of P. dilectus and also to find out suitable live feed for higher survivability of larvae, their metamorphosis and juvenile production under captive conditions with a view to develop a reliable captive breeding and rearing techniques for its mass scale production.