Slender Sardine cichlids

Lake Tanganyika is so full of cichlid variety, and the so-called sardine cichlids of the genus Cyprichromis don’t disappoint. Contenders for the most un-cichlid-like looking cichlid of them all, the sardine moniker also does well to describe these slender, open water fish. 

Lake Tanganyika endemics, Sardine cichlids congregate in huge shoals in open water, where they feed on zooplankton. Shoals maybe thousands strong, offering strength in numbers when faced with the constant onslaught of predatory birds, predatory cichlids, and man. 

Females and non-breeding males are plain to disguise their outlines in the Abyss, but sexually active males sport bright blues and yellows on their fins and tails in order to court females. Cyprichromis are maternal mouthbrooders, so no big surprise there considering the African rift lake they live in, but what is unusual is that Cyprichromis leptosoma don’t need rocks or substrate to lower themselves onto, drop eggs and then quickly pick up them up into the female’s mouths.

Instead, large eggs are dropped one at a time into the water by the females, after snapping at quivering male anal fins. The females then back-up and spiral downwards, snapping up each egg as it is ejected. This same spawning behaviour can be seen in the aquarium too if you are lucky, but the real draw with these fish is the spectacular male colouration.

Species 

Females, juveniles and nonbreeding females are very nondescript, pale, grey-brown in colour, but males in breeding dress can turn on bright blue, bright yellow or even both colours, depending on species. Three species are recognised, C. leptosoma, pavo, and microlepidotus, but there are many geographical variations of each, and a few undescribed species too.

Of those, the first species I kept, Cyprichromis leptosoma is my favourite, and males can come with either blue or yellow tails. These are probably the most widely available in the shops too, followed by “leptosoma jumbo”, which can come with yellow tails, blue tails, all yellow fins, all blue fins, or even all blue, or all yellow bodies! What’s more several Cyprichromis species will swim and feed together,  and even breed next to each other in the lake, so how natural hybridisation doesn’t occur, and females can choose the right male of their species when even they are sporting differing colours, I have no idea. 

Courting three dimensions

Fascinating also is the breeding behaviour of the males. Being open water, non-substrate-dwelling fish, Cyprichromis form open water territories, with no hard surfaces to defend, and in three dimensions. Sexually active males space themselves out into one metre by one metre by one metre, cubic territories, where they hold their place in the water column, display, entice females into their space while at the same time keeping rival males out.

We don’t get to see this in the aquarium of course, as at best we cram several males into tanks which may offer just one-quarter of that three-dimensional volume. If only a public aquarium, somewhere, someday, could offer over one of its 10 metres deep, one million litre display tanks to the fishes of Lake Tanganyika, where we could get to see this behaviour, without having to learn to dive and travelling to East Africa… 

Tank set up

So open water space is critical when keeping sardine cichlids, especially if you want to see hints of that natural behaviour. Fully grown at 12cm for the largest species, Cyprichromis require an aquarium of at least 120cm, and they should be kept in shoals, ideally of ten or more individuals. Rocks are not necessary, although some rockwork always helps to create the illusion of the rocky Tanganyika lake, and authentic-looking rocky background inserts can look particularly effective. 

Lighting should be subdued – the males will display brighter colours then too – and I always prefer marine spectrum lighting on my Tanganyika tanks, again to add that deepwater illusion. Filtration should be capable of adequate mechanical and biological filtration, so an external canister filter is best, plus some carbon to keep the water looking clean and free of yellow colouration.

Cyprichromis don’t mind flow. Due to the size of lake Tanganyika it behaves like an inland sea, and currents can be considerable. Keep aeration high at all times too, so either fit a venturi to the filter outlet or add air from an airstone. Tanganyika cichlids don’t tolerate low oxygen levels. 

Water temperature should be 24-26C and hard and alkaline at all times, pH 8.2-8.5. In soft water areas, buffering materials like dolomite, oyster shells and limestone will help keep the water hard, and Lake Tanganyika “salts” can be bought and added to water change water. 

It is always tempting to add plants to bare or rocky Tanganyikan tanks, but it isn’t biotope correct, and Cyprichromis won’t want or need them. Heavy planting would actually get in the way of their displaying.

Tankmates 

With a group of ten fish, I would aim for three males and seven females. If you are lucky enough to be able to house 20 fish, and they are easily bred, the male to female ratio can rise to 50:50. I would have said never to mix Cyprichromis species due to the risk of hybridisation, but they manage to coexist in the same shoals in the wild without doing it, so it’s up to you.

In large spacious tanks, the more Cyprichromis individuals, the merrier. Fiery males will chase each other and make physical contact, as they mouth each other’s flanks. This may result in the odd split fin, but you won’t end up with males which have been beaten to death, like you would with Lake Malawi mbuna cichlids. 

I would certainly go for a Lake Tanganyika biotope tank every time, when selecting tank mates for Cyprichromis. Altolamprologus calvus and compressiceps work particularly well, and will benefit from the regular brine shrimp, mysis and krill frozen foods that you could offer the sardines. For other lamprologines like Julidochromis and shell dwellers the tank would have to be sufficiently large, and the open water area sufficiently far away enough from rock or shell territories for the Cyprichromis to avoid being snapped up, and to be allowed to do their own displaying unhindered. Sand dwelling Xenotilapia make good tank mates.

Steer clear of Tropheus, they inhabit shallow, rocky areas in the lake and are too territorial. More important is the vegetarian diet Tropheus require, which is in direct compromise of the small meaty invertebrate foods the Cyprichromis need. Frontosa are said to predate Cyprichromis at night in the lake, although after keeping many frontosa, I find them the least predatory, predatory cichlid of all, at least in aquariums that is. Large Cyprichromis with small to medium Frontosa would be fine. Just avoid extremes in size difference. 

Breeding

Keep as few as one male and two females, and when mature, they will breed. The female’s buccal cavity (throat) will distend as soon as she takes in eggs, and will clearly be visible. The fry are huge when spat out, so numbers will be small. You won’t need to intervene unless you don’t have a spare tank and fear predation of fry in the main tank. Skilled hands can “strip” a female of either unhatched eggs or developed fry, and keepers these days have the benefit of being able to purchase egg tumblers – ready made protective perspex boxes which use water flow to spin eggs or fry, oxygenating them like they would be in their mother’s mouths.

Potential pitfalls

I think the first potential problem with Cyprichromis is at point of purchase. You will be able tell C.leptosoma from sp.Jumbo for example in the shops (take a reference book,) although even an expert would struggle to pick out regional variants in mixed groups – especially as they can come in both blue and yellow. Buy from a cichlid specialist who orders and receives them in separate batches, and then keeps them separate. You need to know what you have, so that when you breed them you can pass them on and tell the new recipient exactly what they are. 

Price may put you off but you do need them in groups, and it could be argued that captive welfare would be improved when keeping these fish in number, as much as it would when keeping tetras together.

Avoid small tanks and aggressive tankmates. I added Cyprichromis to a 30” tank with lots of resident Neolamprologus many years ago. They had established territories and my newly added leptosoma were not received well. Aquascaped heavily with rocks they could also not go anywhere that wasn’t owned by someone.

Factfile

Name: Sardine cichlid

Scientific name: Cyprichromis spp.

Origin: East Africa, Lake Tanganyika endemic

Size: Males up to 12cm, depending on species. Females smaller

Tank size: 120cm long, 60cm tall or taller

Water parameters” Temp 24-26C, pH 8.2-8.5

Tankmates: Altolamprologus or Xenotilapia 

Breeding: Non-pair forming maternal mouthbrooders. Males display to females. Females don’t eat while carrying eggs and fry.

Notes: These cichlids don’t look like cichlids or behave like them, shoaling in their thousands in open water, in the wild. Although the females are plain the males can develop bright blue or yellow colours to attract them, and any Lake Tanganyika fan should keep them at least once. 

Featured image Mario Rubio García [CC BY (https://creativecommons.org/licenses/by/2.0)]