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January 26, 2012

The Democratic Republic of the Congo receives the highest amount of precipitation in the world with up to 80 inches of rainfall annually in some areas. This tropical climate is home to the ninth longest river in the world, the Congo River. The river and its tributaries occupy nearly all of the country by covering almost 390,000 sq. mi, and were formed 1.5-2 million years ago during the Pleistocene era. It is here many animals call home, including the great apes like the Western Gorilla (Gorilla gorilla) and the Common Chimpanzee (Pan troglodytes).

Setting up an African biotope can be fairly easy once you’ve figured out what species you’d like to keep. For my set up, I’ve chosen a 75 gallon from Aqueon Aquarium Products. With a footprint of 48x20x21, the aquarium will give the Characins enough swimming space while providing adequate space for the Mormyrid and the cichlids to grow. The Congo River is very dimly lit in most places and covered with a lot of rocks. I’ve stacked several large smooth stones to near the top of the tank and placed Anubias plants in between the crevices and added a few branches of wood to simulate the river habitat. I decided to go with a simple AquaticLife dual lamp T-5 fixture just to help keep the Water Lettuce at the surface strong and healthy while allowing the other plants a sufficient amount of light. Now the water flow is rather swift in the Congo so it would be a good idea to over filter this aquarium with an Ehiem Professional 3 series. I’ve also added a power head in the opposite corner to help keep the current strong. The water has checked out with the appropriate water chemistry and we’re ready to add some fish, so let’s get to it!

Boulenger first described Phenacogrammus interruptus “Congo Tetra” in 1899 coming from slightly acidic and murky waters of the upper Congo Basin. This fish has been available in the aquarium trade for many years now and most of what is found in the hobby today is commercially bred from farmers out of Asia and Eastern Europe. These fish are often over looked in an aquarium shop for having a drab silver body color, but as the males mature to their 3” size, they develop long white fin extensions and a blue/green tinted body that “flashes” against a dimly lit tank. Females are less attractive and slightly smaller at 2.5” and keep their drab silver appearance. Congo Tetras are shoaling fish that can be very skittish if not kept in larger numbers. They are not picky when it comes to their flake food, but feeding brine shrimp (live or frozen) as a treat would keep that sparkle ever so bright in the tank.

 Phenacogrammus interruptus

In the streams and rivers of nearby Nigeria, you’ll find the Arnoldichthys spilopterus “African Red Eye Tetra”. These 3” plus sized fish require plenty of swimming space near the top of the tank. With the tannins leaching out of the wood, these vigorous Characins have started to show their beautiful brown and gold color on their body. The dorsal and anal fins have taken that striking yellow and black hues to make the fish truly stand out against their large black edged scales. Like its cousin, the Congo Tetra, they are rather unfussy when it comes to their diet, but should be fed a varied diet to keep the fish in good health. They are rather adaptable to pH and can be kept in values of 6-7.8. They too like to be kept as a school - so make sure to get a good group!

Arnoldichthys spilopterus 

In the fast flowing streams and pockets of the lower Congo, the Steatocranus casuarius “Buffalohead Cichlid” is found resting near caves and tunnels. For what the fish lacks in colors of a gaudy nature, they make up for with an abundance of character. With a reduced swim-bladder, the Buffalohead is often observed “bouncing” from rock to rock in search of food and a possible mate. They’ll eat just about anything, but providing the nutrients of bloodworms and brine shrimp will get those males to grow their almost 5” size. This diet will also be what the gals need to reach their 3” stature. Though the male Buffalohead’s may look intimidating with that large “hump”, they are actually a relatively peaceful fish that can be housed in a community tank with fish of similar size.

Steatocranus casuarius

There isn’t much information available on the Mormyrids of Africa. Through my research on these “Elephantnose” fishes of the continent, I could not determine what the correct river system is for Petrocephalus simus “Round Nosed Mormyrid”. One article mentioned it was limited to the entirety of the Ogooué River in the Lower Guinea province. Another suggested it was recorded from the Luongo River in Zambia. It appears this is one of the smallest within its family by reaching a maximum length of less than 5”. There has been one very uncommon observation that all of us have noticed from these unusual creatures – they not only come out during the day, but they school together! I watch them in the tank with their cichlid companions and constantly watch them swim together around the tank. This is very uncommon because most of the Mormyrids are nocturnal and don’t get along with one another. So, I may not have been able to determine the origin, but I sure found an “elephant” that I’ll be able to house!


We’ve come to end of the great Congo River and another newsletter. Like always, be sure to check out the products link for our updated price list. You’ll find a few more Mormyrids and West African fishes there. Don’t forget to keep up on your regular water changes, and I’ll see you back here next week…

Anthony Perry
Sales Manager