Betta Trading

 Congo Tetra 

The Congo Tetra, Phenacogrammus interruptus, comes from the middle of the Congo River basin.  The Congo River is also called the Zaire River.  In total flow it is the second biggest river in the world.

The Congo Tetra is found in the Democratic Republic of the Congo, and maybe in the Republic of the Congo.


The Congo Tetra is one of the largest tetras.  The male will grow to 8 cm (3 inches) while the female will reach 6 cm (2.5 inches).

Water Conditions

The Congo Tetra will tolerate a good range of conditions.  A pH of between 6.0 and 8.0 is all right.  They do not mind a reasonable amount of hardness; 5-19 dH is suitable for maintaining the adults.

The Congo Tetra is a tropical fish and needs water that does not get cold.  An aquarium heater with the thermostat set on between 23 and 26 degrees C (between 73 and 79 degrees F) is recommended.


In the wild, the Congo Tetra is an omnivore, eating insect larvae like mosquitoes, small crustaceans like Daphnia, small worms and algae.

In an aquarium, it will eat normal dried fish food readily.  A high protein food is to be preferred.  If possible, this should be supplemented with live food like Daphnia and frozen food like blood worms and brine shrimp.


The Congo Tetra is a schooling fish, and generally a minimum of five is recommended.  However, some people have reported that they have kept a pair of these fish and they act as if they are not stressed.

It is a bigger fish than most tetras and I do not recommend keeping it with the smallest tetras like the Adonis or the Neon tetras.

Most of the tetras and the more peaceful barbs are good companions for them.  I have kept Congo Tetras with a Siamese Fighting Fish and Guppies without trouble, but I suspect that this would not always happen, and I suggest caution in keeping slow moving long finned fish with Congo Tetras.

The Congo Tetra is an excellent community fish.

You should also avoid large, aggressive fish like many of the cichlids with Congo Tetras.


The male Congo Tetra has significantly longer fins than the female.  In addition to this general difference, the centre of the male’s tail is longer than the rest of the tail.  The dorsal fin of the male reaches to the tail fin.


The Congo tetra can be bred either in a pair or in a school. In the wild they are probably mainly school breeders.  They readily breed and will often lay eggs in a community aquarium but the owner will normally not be aware of this.

If deliberately setting out to breed this beautiful fish, the breeding tank should have soft, acidic water.  Some people use a peat substrate.  As with many fish, the Congo Tetra will often spawn when the morning light falls on the aquarium.  Unlike many tetras, they seem happy spawning in a brightly lit aquarium.

About 300 eggs are laid per female; they are light brown in colour and would be camouflaged against a peat substrate.  This suggests the possibility that this type of substrate is common in their natural habitat.  The eggs hatch in about 6 days.

Raising the Fry

The babies seem ready to eat as soon as they hatch.  They are big enough for newly hatched Brine Shrimp, finely screened Daphnia, rotifers or similar sizes food.

Least Concern

The IUCN Red list regards the Congo Tetra as a species of least concern although it has no information about how whether or not the population is decreasing.

Pest Fish

Although I am not aware of the Congo Tetra having become a problem, we should always avoid our pets getting into ecosystems that they are not native to.

Other Scientific Names

The accepted scientific name is Phenacogrammus interruptus (Boulenger, 1899).  Other names that have been used are Micralestes interruptus Boulenger, 1899, Hemigrammalestes interruptus (Boulenger, 1899) and   Alestopetersius interruptus (Boulenger, 1899).

Sources and Picture Credits

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IUCN Red List:""> dlist/search