Rachow's nothobranch (Nothobranchius rachovii) belongs to a group of fish collectively referred to as killifish.
There are several genera of killifish (e.g., Aphyosemion, Epiplatys, Aplocheilus, Nothobranchius, Cynolebius, and others) that all belong to the family Aplocheilidae. There are many species within each killifish genus and the fish of each genera have different breeding habits and life spans.
For example, all members of the genus Nothobranchius have short life spans. The killifish in this genus die at the end of the breeding season, whereas other killifish may live for a few years. Because of their short life span, Nothobranchius spp. are often referred to as annuals.
The genus Nothobranchius contains over fifty species of killifish, however, this article will only go over the specific care requirements of Nothobranchius rachovii. Their care and breeding requirements may overlap with other species in this genus.
Rachow's nothobranch are from Africa. In their natural environment they inhabit lakes or ponds that evaporate during the dry season. Before their water dries up these killifish lay eggs in the mud. The adult fish die when their water source dries up, but the eggs survive during the dry period. In fact, these eggs must undergo a dry period in order to hatch. When it rains again a few months later, the ponds or lakes refill, and the killifish eggs hatch.
If you attempt to breed Nothobranchius spp. in your aquarium you will need to remove the eggs and store them for awhile in order form them to hatch.
To breed these killifish you must have a peat substrate (at least 2-3 inches) in your aquarium. The killifish will bury their eggs in the substrate. Afterwards, you must remove the eggs and peat from the water and store them in a plastic bag or some other container for a period of time. After about 3-4 months put them back into the water and the killie fry will hatch.
Rachow's nothobranch are typically small fish that reach an adult size of about 2 inches (5.1 cm). They need soft, slightly acidic water (pH about 6.5). You should have peat as the substrate for them to lay their eggs in and this will help to maintain the proper water conditions as well. They need a water temperature between 74-79 ° (23-26°). A heavily planted species only tank is probably best for them, although they are peaceful fish.
These killifish show some variability in coloration, and males are much more colorful than the females.
They are carnivores and will eat most live foods (e.g., brine shrimp, worms) and will also accept freeze-dried, frozen, and flake foods.
Although their water source won't dry up in the aquarium environment, these fish still have short life-spans - about 1 to 1 and ½ years at most.
You can't usually find any species of killifish for sale at most mainstream petstores. However, you can generally find them online for about $40 for a male-female pair. Because the Nothobranchius spp. eggs store so well you can often obtain the eggs from other hobbyists online.
Once the killie fry hatch they can be fed newly hatched brine shrimp.
For more information on hatching and raising killifish fry please visit the American Killifish Association.