By Mark DelRaso, GCKA/AKA
This article first appeared in the GCKA Newsletter in March 1990.
Breeding killies of the subgenus Diapteron (Huber & Seegers, 1977) is not too difficult once certain conditions are met. The first problem that arises is finding good stock that is mature. Sexual maturity in the Diapteron subgenus is reached at nine months to one year of age. Even if eggs are picked or transferred without touching them, [eggs laid] at an early age will result in fungusing. Diapteron georgiae (Lambert & Gery, 1967) is the easy one to spawn at seven to nine months of age. However, viability of the eggs and the resulting fry is noticeably poor. With this particular species, viable fry and eggs are produced at an age reaching over one year. An additional point to be made is that the fish in this subgenus are rather long-lived. The oldest specimen kept by me currently is a healthy five and a half year old female D. abacinum (Huber 1976). D. abacinum is also the most challenging to breed beyond the first generation from the wild. According to some experts, D. abacinum may not be a valid species due to crossing. I am not sure about this because of the same problem with the Aphyosemions in the bualanum/dargei group. To breed these fishes, the aquarists must follow certain guidelines to care for their Diapterons. Once the conditions are met, you will be able to propagate these killies for several generations.
The first item on the checklist is suitable temperature. These fishes are from cool highland forest brooks in Gabon. In this biotope, heavy shade provided by the forest canopy prevents direct solar radiation from heating the water above about 70° F. A constant fishroom temperature of 68° F is the magic number. If you cannot give these fish a water temperature of less than 70° F, then you should not attempt these fish. At temperatures above 72° F, Diapteron do not keep their body weight.
The second requirement for these fish is very dim lighting. This is due to the effects of the very heavy forest canopy. The aquaria that you keep these fishes in may be sidelit from another tank to the point of recognition of the bottom of the tank. Some Diapteron specimens will do well in a tank bright enough to barely grow Microsorium pteropus and Anubias nana. The water should be quite soft and acid. You can use rainwater filtered through a high quality carbon to remove pollutants. To keep them comfortable, a pH of 5.5 to 6.2 is required. The hardness should be less than 50 ppm. More specifically, the carbonate hardness should be less than 2° DH and the general hardness less. The water must be very clean – no metabolites.
The third requirement is the proper foods. While white worms and grindal worms can be fed occasionally, crustaceans are the primary diet in the wild. Rinsed artemia nauplii are excellent foods for both the fry and adults. Daphnia is the best food, however. The Diapterons do not accept prepared or frozen foods. This is another requirement: LIVE FOOD ONLY. I feed all my killies live foods most of the time. So I always feed the Diapterons first if I am running low on live food. It is neat to watch a male D. fulgens stalk a baby brine shrimp.
After you have met the above conditions, you can pick the eggs very carefully or scoop the fry. I suggest you scoop the fry or transfer the mops, floating and sunken, to a container with water from the adults’ tank. The fry can be very nasty and cannibalistic. Remove the largest fry if it becomes a problem. Usually, if you keep a lot of mop material in the rearing tank, you will end up with a colony that will get along together.
There is a sex ratio problem with fry from young pairs. The first batch is very long in males. After the pair has been producing for one and a half to two years, the problem is much less pronounced. My last batch of D. fulgens was actually long on females. This works out well for young males of the next group of fry paired up with older females.
Remember: breeding these fish is a project taking at least one and one half years. Feed live food. Keep the tanks dim. Maintain soft, acid, and cool water. Use floating and sunken mops. Try not to touch the eggs. Enjoy the following Diapterons in the order of increasing difficulty:
A. (Diapteron) georgiae (Lambert & Gery 1967)
<A. cyanostictum (Lambert & Gery 1967)
A. fulgens (Radda 1975)
A. abacinum (Huber 1976)
Note: A. (Diapteron) seegersi (Huber 1980) has not been in the hobby for quite some time. There is confusion as to its validity as a species with some people. Also, there are some new locations of undescribed Diapterons making their way into the country currently: A. (Diapteron) sp. GBN 88/29 and one other species I am currently breeding. – G.C.K.A. Newsletter, June 1999