Taxonomy & naming
Lethrinops sp. "Rainbow Tanzania" is a hobby label for an undescribed Lake Malawi haplochromine. It has no formal description. Christen (2006) reports that the form was probably imported into Germany only once, in 2003, under the name Lethrinops sp. "Blood Spot". He suggests it may be closely related to Lethrinops sp. "Dwarf Mbasi Creek", which had reached the trade sporadically before. The atlas has a separate page for Lethrinops sp. "Mbasi Creek".
Morphology
Newly arrived males measured 3–4 in TL and females 2.5–3 in. All looked grey with a light blue sheen. Males differed only by a clear red edge on the dorsal and anal fins and more egg spots in the anal fin. Females also carry a few small, weak egg spots there.
A settled, coloured male has green-turquoise flanks and nine dark vertical bars between the gill cover and the tail. A red spot sits just behind the gills above the pectoral fin, which probably gave the import name "Blood Spot". The dorsal and anal fins have an orange edge, and the dorsal carries orange spots. During territorial disputes the unpaired fins and pectorals turned almost black, so the orange dorsal spots and anal egg spots stood out. The largest male reached a good 5.5 in; females stayed around 3 in (Christen 2006).
Habitat
This is a Lake Malawi fish, and both sources describe it as a sand dweller. The trade name points to the Tanzanian part of the lake, but the sources give no collection site.
Feeding
Aqua Haus Gaus describes it as a sand-sifter over open sediment. The seller says it takes sand into its mouth, filters out tiny invertebrates and expels the sand through the gills. Christen's fish sifted the substrate all day. In his tank they took good granules and frozen food without problems.
Mating
The dominant male dug a spawning pit in a corner near a stone and piled sand into small mounds around it. He lured a ripe female with vigorous shaking and spread fins, and the pair spawned in the typical mouthbrooder circling. Rival males circled with spread fins, made mouth-to-mouth threats and mock lunges. They caused no serious bite wounds and no wild chases (Christen 2006). Aqua Haus Gaus says males show an iridescent rainbow of colours in courtship.
Breeding
The male spawned with all four females over several weeks. In a rearing tank at about 75 °F the females released their young after a good three weeks. Broods held 10 to 30 young, depending on the size of the female. The females cared for the young for the first days and took them back into the mouth when threatened. After three to four days they ignored them.
After about three months courtship stopped and the group schooled again. Small fights followed weekly water changes. Christen wonders whether the fish have a breeding season in the wild.
In the aquarium
Christen kept a group of 4 males and 4 females, offspring of wild fish. They were very shy, schooled tightly and startled at any movement in the room. They stayed pale for months. Adding Aulonocara baenschi "Benga" did not help, because the Aulonocara adopted the Lethrinops' shyness.
In a quieter 120 × 23.5 in tank with 1–1.5 in of sand, a few stones at the edge and no direct lighting, a male coloured up within hours. Adding a group of Aulonocara maylandi (2 males, 5 females) made the fish bolder. Christen's advice: a quiet location and a large group are essential, and a sand bottom is required because the fish sift all day and the males build pits.
Conservation
The form has not been evaluated by the IUCN. Nothing is known to the atlas about its wild status or range.