Matt Clarke on one of the unusual tilapiine cichlids from Lake Bermin, a tiny volcanic crater lake in Cameroon.
Scientific name: Tilapia (Coptodon) bythobates
Origin: This species is endemic to Lake Bermin, a tiny 700m wide volcanic caldera in Cameroon, West Africa.
Size: This species reaches 10-15cm/4-6" in captivity, so it's a fraction larger than some of the other Bermin tilapiines.
Diet: Mainly plants and algae - strongly herbivorous. Mine like peas, but also take spirulina flake and Tetra Prima. Said to be fond of blanketweed, too.
Habitat: Found in the deepest parts of the lake - minimum 8m/26' - and apparently adapted for life in lower oxygen waters with a higher level of haemoglobin in its blood.
Water: Lake Bermin has a pH of around 7.5 and is fairly soft (80 microsiemens). The lake contains bogwood, leaves, plant detritus and volcanic rocks. Mine are doing well at pH 7.1, GH 4, 25C.
Aquarium: I have a group of four of these, currently temporarily housed alongside some other rare West African tilapiines in a 90cm/36" tank furnished with silver sand and inert rocks. Soon to get a tank this size to themselves.
Identification: Pete Liptrot of the Bolton Museum Aquarium tells me that the fish I obtained are probably offspring from his fish, which he previously believed to be T. gutturosa, another Bermin endemic. Pete says the fish were collected by Oliver Lucanus and identified for him as bythobates by Dr Uli Schliewen, one of the people who described the species. Dr Anton Lamboj also took a look at my fish and reckons that they are probably also bythobates. The fish are have bigger heads than T. snyderae and a rose colour on their operculums, head and flanks.
Breeding: There are no published reports of aquarium spawnings. Pete Liptrot told me: "They can get quite pugnacious, they're highly fecund and will demolish plants with enthusiasm, but they're bonny little beasts!" He says they'll spawn on almost any surface, not just inside caves or rock crevices as some other Bermin cichlids do. Mine have recently spawned. The pair layed their eggs on the underside of a rock and excavated a small pit. For their size, the fish are remarkably aggressive when spawning and the female, which measured about 5cm, had no problems in seeing off a male Tilapia discolor measuring 20cm, and about ten times her bulk! About 100 eggs were laid and the fry were guarded by both parents for a couple of weeks.
Sexing: When coloured-up, some minor differences are apparent between the sexes. The males look slightly deeper and longer, and their dorsal fins look a little longer. Females become plump prior to spawning and have a tilapia-spot, plus a clear ovipositor. In breeding condition, the sexual differences are much more marked.
Conservation status: These are on the IUCN Redlist and are classed as vulnerable. This is largely due to the small size of their natural habitat.
Availability: Extremely rare. These were on sale as Chromidotilapia guttoroso at Aquascope in Lancashire.
Price: One particularly useful thing about these is that they're so rare that not many people know what they are, hence the attractively low pricetag of about £10!