Lethrinops microstoma was first described by Trewavas in 1931. The genus name Lethrinops can be broken down into two parts. ‘Ops’ means ‘appearance’ and Lethrinus is a reference to the genus of saltwater fish Lethrinus (Lethrinidae), which they somewhat resemble. Together they give the meaning that these species have the appearance of the genus Lethrinus. The species name microstoma also consists of two parts. ‘Micro’ means ‘small’ and ‘stoma’ means ‘mouth’, a reference to the small mouth of this species.
Two other names are used in the trade: Lethrinops Aurita and Lethrinops sp. yellow black dorsal.
Lethrinops microstoma remains somewhat smaller in the wild than in the aquarium. In Lake Malawi, the males can grow to about 15 centimetres in length. In the aquarium, they usually get more and more powerful food. As a result, the males grow to about 17 centimetres. The females remain somewhat smaller than the males and grow to a maximum length of about 13 centimetres (in the wild a maximum of about 12 centimetres).
The colour of a dominant male is more subtle than many other Malawi cichlids. They get a blue head. The flank shows a metallic green/blue with vague vertical bands. The dorsal and caudal fins are orange/blue mottled. The upper edge of the dorsal fin shows a white band with a black streak underneath. The anal fin becomes darker with clearly visible egg spots.
The colour of the Lethrinops microstoma females is similar to that of other Lethrinops species. They remain brown/grey in colour. There are often some dark spots on the flank.
Lethrinops colouring in the wild
Lethrinops are inhabitants of the sandy plains in the wild. Here they live in the safety of groups. The predatory fish always try to focus on one prey. Selecting prey in a group that all looks the same is very difficult. Therefore, in the wild, Lethrinops often look dull and similar silver in colour. The males only get their brilliant colours during the spawning season.
Lethrinops colouring in the aquarium
In the aquarium, Lethrinops are very gentle fish. They are soon suppressed and then lose their colour. If you keep them in an aquarium with other Malawi cichlids, it will quickly become too crowded. To bring out the colour of the Lethrinops, it is best to keep them in a special aquarium. One or more males and several females.
They are still Malawi cichlids. The males impress each other to determine their ranking. They normally do not chase each other. They spread their fins wide and with open mouths, they argue a little. They swim in front of or next to each other to determine who is the dominant male.
The colours of the males show best without other fish species around. If you still want to keep other fish species with Lethrinops, try calm Aulonocara or Copadichromis. Even then there is a chance that the Lethrinops will not come to colour.
This species is endemic to Lake Malawi. They inhabit the moderately shallow waters of the transition zones above the sand during the breeding season. Outside this period, Lethrinops microstoma probably migrate to deeper waters.
In the wild, Lethrinops microstoma feeds on invertebrates and insect larvae that reside in the sand. To do this, they bite into the substrate and sieve it through their gills.
In the aquarium, it is not a picky eater. As long as you give them a variety of different foods to keep them healthy. You can feed them mosquito larvae, brine shrimp, snails, spirulina flakes, granules and the like.
As explained above, it is best to keep Lethrinops microstoma in a species aquarium. That is, without any other species. In this way, the males show their best colour.
Use an aquarium with a minimum length of about 150 centimetres for this. You can keep a group of two to four males in an aquarium this size. Place about two to three times as many females as males.
Set up the aquarium with (filter) sand on the bottom. Lethrinop’s microstoma sieves the sand in search of food particles. With rocks, you can create some caves, cracks and crevices. The females use these caves to hide from the attention of the males.
Provide plenty of fresh water. The temperature may be between 22 and 26 degrees Celsius. The pH is preferably between 7.5 and 8.5.
The lighting does not have to be very strong. Plants do not really occur in the biotope of Lethrinops microstoma.
Breeding Aquarium and Condition
No special aquarium is required for the cultivation of Lethrinops microstoma. They reproduce in the company of conspecifics or other species.
In the wild, Lethrinops microstoma breed only during the breeding period. In the aquarium they usually breed all year round.
In the wild, the men build a sand castle in a sort of breeding colony. These are usually found in shallow, sheltered coves. This sand mound has a kind of pit on top in which the couple can deposit the eggs. The Lethrinops microstoma male defends this stronghold fiercely against other Lethrinops microstoma males.
When females swim through the breeding colony, they are approached by the males. The males try to seduce the females to go with them to their sand castle.
The castle is abandoned at night. Probably to prevent catfish from finding and eating the male at night. The males then join the foraging females.
As soon as the male notices that the females are ready to lay eggs, he chooses a spot in the sand under a rock. He defends the spot against the other males.
The Lethrinops microstoma male is now getting his most beautiful colors. To show it to the women, he spreads his fins wide. With trembling movements, he shows his colours and fins to the female. With this, he tries to lure her to his chosen place to spawn.
The couple circles around each other until the female is ready to lay eggs in the sand. After laying a few eggs, the flock continues to turn. The female picks up the eggs to incubate them in her mouth.
The man spins, sweeping his anal fin across the sand. Egg spots are visible on the anal fin. The female snaps at the egg stains, assuming they are eggs that she has just laid. The man releases some sperm and fertilizes the eggs in the female’s mouth.
Raising the fry
The eggs hatch in the female’s mouth after a few days. The young Lethrinops microstoma do not leave the female’s mouth for about three weeks. Until then, they largely live on their egg yolk sac. The female releases them when everything is safe. The young can hide in the female’s mouth for another one or two weeks if there is danger. After that, they really have to take care of themselves.
In the aquarium, you can feed the young Lethrinops microstoma with crushed flake food and small live food such as brine shrimp. As they get older, you can feed them with increasingly larger food.
This species can show brilliant colours when they feel comfortable. They are therefore best suited for a special aquarium. If you meet their requirements, the colours can splash off. Therefore, only consider keeping this strain if you are willing to give them the space and tranquillity they need!
John de Lange