The Yellow-edged Lyretail Grouper (Variola louti) is also known as the the Lyretail Grouper, Common Lyre-tail Cod, Lunar-tail Cod and Lunar-tailed Rock-cod. They are reasonably common on the Tanzanian coast but are more common on the offshore Islands such as Zanzibar and Mafia Island. Being very colorful they are one of the more attractive looking groupers. Their appearance changes fairly dramatically from the juveniles to the adult and these changes are shown below.
The juvenile Yellow-edged Lyretail Grouper pictured above has a yellow lower body with a slightly darker yellow brown upper body. From behind the gills there are a series of dark black blotches on the mid body and a prominent circular black spot on the caudal area. The entire body is covered in blue spots.
As can be seen in the image above, as the fish ages so the body color reddens and the edges of the anal, dorsal and caudal fins go yellow.
When they are fully mature the body background color is a mix of yellow with irregular red markings. The spots are more of a purple color and overall they are a very attractive looking fish.
As with all grouper they have a proportionally large mouth designed for swallowing their prey whole and they have a row of proportionally small teeth in the front of their mouth. They are one of the larger groupers and their maximum length is 100 cm and at this size are usually around 12 kilograms.
YELLOW-EDGED LYRETAIL LEOPARD GROUPER IN THE WILD
In Tanzanian waters, the Yellow-edged Lyretail Grouper is normally found below 12 meters in depth. They are usually seen singularly and the juveniles hide in branching corals and under overhangs. The adults are normally seen swimming just above the substrate.
Yellow-edged Lyretail Grouper are found from the east coast of Africa including the Red Sea across to Southern Japan, down to the west and east coasts of Australia and eastwards to the Pacific Islands excluding Hawaii. They are typically found on deeper exposed reefs rather than in protected areas or estuaries. They are found from 2 meters downwards to 250 meters.
Their main diet comprises of fishes, crustaceans and stomatopods however given they are caught by fishermen on the hook this indicates that they will scavenge as well. They are primarily ambush predators and feed in the early morning and late afternoon when their coloration gives them more camouflage. Red light is filtered out by the water after about 5 meters and their redish colours provide good camouflage deeper underwater.
Little seems known of their breeding behaviour but spawning aggregations have been seen in the Seychelles. These aggregations have consisted of between 10 to 100 fish. The eggs are released into the substrate.
The Yellow-edged Lyretail Grouper is fished by local fishermen both by line fishing and using nets and traps and in most areas of the Tanzanian coast is heavily over fished. In some areas they have been noted to have a concentration of heavy metals.
Heemstra, P.C. and J.E. Randall, 1993. FAO Species Catalogue. Vol. 16. Groupers of the world (family Serranidae, subfamily Epinephelinae). An annotated and illustrated catalogue of the grouper, rockcod, hind, coral grouper and lyretail species known to date. Rome: FAO. FAO Fish. Synop. 125(16):382 p. (Ref. 5222)