The royal gramma is such a common and low profile fish, that news of this fish’s successful breeding may not register on the popularity radar. However if you are a fan of Gramma dejongi, or live in Australia, captive bred royal grammas being produced on a commercial scale is very exciting news indeed.
Here we have some photos from the first large settlement of grammas bred at the Batavia Coast Maritime Institute, (BCMI). The Institute has been working hard to breed many different species of reef creatures, especially those that are very rare or hard to get in Australia.
Royal grammas might be a starter fish with a retail price of $10 to $20 in the U.S. but around the world, the price for a royal gramma can reach as high as $60 to $80, making it an ideal candidate for captive breeding efforts. Despite being a hardy aquarium fish, royal grammas have a unique breeding strategy and behavior which is unlike the pelagic and demersal spawners which produce hundreds or thousands of eggs per spawn.
Instead royal grammas spawn in a cave, and generally lay between 5 to 40 eggs almost every night. The BCMI has had novel challenges to overcome with the breeding of royal gramma especially due to getting the broodstock to lay clutches of eggs at regular intervals.
The biggest challenge with breeding royal grammas is not getting them to spawn, it is rearing and growing out the larvae and juveniles. Since the eggs are laid in small numbers and in sequence, a growout tank of grammas can include juveniles of varying ages, and very different sizes.
The size difference between the young fish of various ages results in a wide variety of mouth sizes, and therefore different food items that can be offered to the growout of these captive bred fish. The fish are first offered copepods which is supplemented with traditional feeds such as enriched large strain rotifers and enriched sep-art Artemia nauplii.
The grammas are still currently in the larval nursery area and will be shifted to the grow-out soon once a suitable spot in the raceways has been cleared. The BCMI are hoping to keep the gramma as a regular on their Australian captive bred pricelist once they are added, which could happen as soon as later this month or early August.
Despite gramma species being easier to breed but with their own challenges when it comes to raising up more than a few specimens, we still haven’t heard any news of the illustrious Gramma dejongi being bred. Perhaps these promising results in rearing commercial quantities of Gramma loreto will be translatable to growing its Cuban congener so that one day both species will be commonly available from captive breeders.