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Just found a piece on the Practical Fishkeeping magazine website covering a VERY unusual Cichlid spscies.

Alcolapia (Oreochromis) alcalicus

For those who are looking for a Cichlid with a difference, this could be just the ticket. However, a word about it's native habitat is apposite here ...

This fish hails from Lake Natron, which is situated in Tanzania close to the Kenyan border. This lake is famed for being the only known breeding ground of the entire world's population of 2.5 Lesser Flamingoes, which build their nests on alkaline sodium carbonate deposits rising from the lake waters. If that makes your eyes pop out on stalks, then it should ...

The ambient conditions in Lake Natron make the hard, alkaline waters of Lakes Malawi and Tanganyika seem tame by comparison. At the peak of the dry season, when the water has receded due to evaporation, the lake is at a pH of - wait for it - 10.5. This is as alkaline as a laboratory solution of pure ammonia! The carbonate hardness is WAY off the scale of most test kits - how does a carbonate hardness of 7,280 strike you? Yes, this water is, basically, a solution of sodium carbonate and other minerals deposited into the lake from volcanic hot springs. Temperature is another interesting factor - away from the hot springs, the water is around 32 degrees Celsius, but near the hot springs where the thermophilic cyanobacteria grow, the water temperature can hit 50 degrees Celsius with ease.

To cope with the extreme living conditions, Alcolapia alcalicus has a number of interesting adaptations. For example, instead of secreting ammonia from its kidneys, it secretes urea, just like humans. Its swim bladder is modified to allow it to extract oxygen from the atmosphere, and it frequently gulps air at the water surface in its hothouse home. The fishes themselves live in the cooler parts of the lake, but make dashing forays towward the hot springs to dine upon some of the aufwuchs growing around the scalding hot vents.

Needless to say, keeping this fish is going to be an interesting exercise. This must be the ONLY fish you will ever encounter that actually requires you to dissolve sodium carbonate in the aquarium water!

Needless to say, the fish is known by the common name of "Soda Cichlid". Defintely one for the collectors among you!

And, apparently, it will breed in the aquarium too. It's a mouthbrooding Tilapia-type Cichlid.

For maintenance, it's recommended to keep it at around 28 degrees Celsius, but breeding requires temperatures of 32 degrees Celsius and up. This is probably the only fish you'll ever encounter that can happily survive temperatures above 40 degrees Celsius in the aquarium ...

When Matt Clarke called this fish an 'extremophile', he wasn't kidding ...




Panda Catfish fan and keeper/breeder since Christmas 2002

Let me just say WOW!!!! That is a pretty fish, man it might be tough to keep under those circumstances. Where does one get sodium carbonate anyway? Is that baking soda? How many boxes would you need? Might not be a bad idea to buy stock in Arm & Hammer to keep this fish. Would that be able to live in the Great Salt Lake in Utah or the Dead Sea? Very interesting.

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~~Melissa~~
"Beauty is in the eye of the beer holder."

That is definitely an extremophile fish! But a very pretty one.

Thanks for sharing Cali!

*Kristin*

Crazyred, sodium carbonate is sold here in the UK as Washing Soda. You'll find quite a bit of information about it here.

Here in the UK, it's made by ICI. I have a packet somewhre that is intermittently pressed into service for hand washing. A quick check reveals that in the US, it's made by Arm & Hammer.

If anyone ever obtains this rare and extremely unusual fish, and decides to mix up a sodium carbonate solution to maintain the fish in, check the ingredients list CAREFULLY and make sure that the product you buy is pure sodium carbonate, with NO additives. While buying the compound from a chemical suppliers as the analytical reagent is expensive, the purity is guaranteed.

A solution for this fish would comprise mostly sodium carbonate, plus perhaps a small amount of sea salt. Add the sea salt first to make up a brackish solution to a specific gravity of 1.002, then add sodium carbonate until the solution reaches a pH of 9.2. This should prove to be a suitable procedure for creating aquarium water for this very unusual fish.

Aquascaping will probably consist of tufa rock. Aquarium should be well lit (primarily to help foster algal growth, as the fish will feed upon algae) and one need not worry unduly about lighting being too bright, as the natural home of this fish is subject to 12 hours per day of blazing equatorial sunshine in addition to the steaming heat generated by the volcanic springs.

To supplement the fish's diet, live Brine Shrimp is probably a good choice - chances are that similar organisms live in the aufwuchs of its natural home. However, I suspect that this fish will be susceptible to a condition akin to Malawi Bloat if fed too much in the way of high protein meaty foods. Algae, vegetable supplements and carefully chosen animal matter are probably the way to go with this fish, reflecting its strange environment and the food sources available to it there.

This of course is likely to prove academic to most of us, as the chances of us obtaining this fish in our collections is likely to be very small. If anyone here DOES obtain this fish, these guidelines should hopefully lead to successful aquaculture.


Panda Catfish fan and keeper/breeder since Christmas 2002