Aphyosemion cognatum CI2011

Aphyosemion cognatum is a beautiful species of killifish from the Aphyosemion elegans group.  The Zaire River drainage south & east of Kinshasa & southern Congo, the lower Kasai River & Pool Malebo are all areas known to contain the species.  It is generally found in streams, pools, and swamps in forested regions.  While it hasn’t been collected by hobbyists since 1991, it is imported regularly; probably due to its proximity to Kinshasa and Brazzaville where many fish are imported from.  In 2011 Jeff Michels (www.aquaticclarity.com) imported the species with only the designation of Congo for location. 

Like most other rainforest dwelling killies it prefers cool, soft, acidic water.  It does seem somewhat tolerant to a wide range of water conditions however.  I currently keep my water around 120-150ppm hardness and 75 °, I don’t check pH.  I raise fry in straight tap water, which for me ranges from 225 to 350ppm hardness. 

A. cognatum readily accepts many kinds of foods.  Mine happily eat flake, granules, frozen bloodworms and Repashay foods.  For breeding I feed them a range of live foods including white worms, black worms, fruit flies, chopped red worms, daphnia, baby brine shrimp and grindal worms.  Fry get baby brine shrimp, microworms and golden pearls and grow rapidly.

This is a plant spawning species and breeding is fairly simple.  They can be bred using a spawning mop.  You can pick eggs and incubate them in water or on damp peat moss, incubation takes 14-21 days.  Another way to incubate the eggs is to pull the mop from the tank, squeeze out the excess water, and store in a Ziploc bag.  When using one of the above methods I like to keep the male and female separate for conditioning and then put them together for a day or two for spawning.  This typically gives a larger number of eggs.

Another method of spawning them is the method I learned from Gary Greenwood & John Metzger, and the method I currently use.  I fill a 2.5 or 5 gallon tank approximately half full of long fiber sphagnum moss.  Usually I will pre-soak the moss until it sinks before adding the fish.  These “natural” setups get large weekly water changes to maintain water quality.  I feed live/frozen foods daily, and these tanks always get baby brine shrimp as well.

Usually within 4-6 weeks I start seeing ¼” long fry hiding in the moss or hovering just above it.  At this point I set up an identical tank and move the parents.  The fry grow fairly quickly and show signs of sexing out at 2-3 months.  Once I see a large number of fry in the 2.5 gallon and they have a little bit of size on them, I will carefully remove the moss, small amounts at a time, by hand.  Once most of the moss is out of the tank, I will transfer the entire contents of the tank to a 10 or 20 gallon tank.  At this point I start feeding the fry grindal worms as well as baby brine shrimp. 

By the age of 5-6 months I’m able to set up new breeding pairs and start the cycle all over again with another generation.  Some strains of A. cognatum are reportedly more difficult to breed, but so far the CI2011 strain has been easy and prolific.  I regularly get batches of 3 dozen or more fry at a time.  If you’re new to killies this is a great species to try.