France’s Marineland Has Rare Captive Breeding of Gramma Dejongi | Reef Builders

France’s Marineland Has Rare Captive Breeding of Gramma Dejongi | Reef Builders

It appears that Gramma dejongi, once a very inaccessible reef fish is about to become a lot more common fish in the reef aquarium world. Right after Biota showed their first captive bred G. dejongi, a French Public Aquarium called Marineland has also managed to breed them.

The broodstock Dejongi came from Dejong Marinelife, in the Netherlands as an exchange for some captive bred sandbar sharks, Carcharhinus plumbeus, born at the Aquarium. They came in November 2018 together with some other species for their established in house breeding program including dottybacks, longnose filefish, cardinalfish, bird wrasse, and a variety of dragonet species.

All theses fish were housed in their specially designed broodstock holding system designed and conceived to properly feed the breeders, and harvest the resulting eggs. It took only 10 months to condition these Dejongi broodstock and get them to spawn. The fish are house behind a large window, so they mostly get natural sunlight.

Broodstock tank is 150 liters or around 40 gallons, and equipped with live rock, PVC pipe, Flower pot, and some Caulerpa prolifera. They are copiously fed, and given live mysis regularly. The fish were 4 cm long when they were placed in their tank.

The male picked a 32 mm wide PVC pipe, some Caulerpa prolifera and some white filter media fiber to make its nest. The female visit the nest but prefer to stay in the pot. The only other habitant of the tank were a couple of Acreichthys tomentosus captive bred in the facility and used to regulate aiptasia.

Larvae are collected in the morning from the larvae collector and transferred into a 800 l mesocosm ‘living soup’ filled with rotifers, copepods and Isochrysis. Larvae were collected for 8 days and added to the mesocosm. They have daily spawning over a few days period.

Metamorphosis happens after 31 days at 26 C. Tubes and other hiding objects must be added to the system as soon as these fish settle. At 39 days all the fish settled, and were collected at 44 days. The survival rate was 50%.

Just Metamorphosed fish

Within a year most species targeted by this program were successfully bred. They are working on other fish, and are collecting a lot of eggs from their display. Most of these fish will enter the exchange program between public aquariums, and there are little chance to see them in a hobbyist tank but luckily Biota is filling that gap.

The young and successful Marineland breeding team is composed of several aquarist including  Jérome Gillet (Which is also the photographer), Sarah Mension, Régis Billion, and a new recruit Laetitia Cluzel under supervision of Jean Philippe Catteau. Good Job Guys! A special thanks to Alain Duday for its great advices, and Cfeed for their great help with Copepodes.

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