Photo credit: Grace Charway (Ghana) Information source: Ismael Radwan (Egypt) Description: Abdel Rahman El Gamal
The two photos show an innovative incubator for the eggs of African catfish (Clarias gariepinus). As shown in one of the two photos, the incubator (about 50×70 cm) is screened from the bottom and for part of the sides. Each incubator accommodates the full spawn of an individual female. The incubator is placed in a plastic container (the one of red color). Fertilized eggs after water hardening, is placed in the incubator whereas water in the outer container and so in the incubator is adjusted at the proper level. The water inside the egg incubator is aerated using a small airstone. Under optimum temperature (28 C), hatching will take place and catfish larvae will swim to the outer container through the openings in the incubator leaving behind the dead eggs and egg shells. The incubator -free of fry- is then lifted from the outer container. Hatched larvae are nursed for 12 days. During the nursing period, larvae/fry are fed on either specialized feed for marine larvae of 200-300 micron size, or artemia or nematodes. A combination of 2 or the 3 of the mentioned food could be used. The 12-days of primary nursing could be carried out in the outer container or fry from several containers -of the same age- could be pooled and nursed in a larger tank. After the 12 days, fry are moved outdoor fertilized earthen pond for further nursing that lasts about a month whereas fry reach to fingerlings of about 2-3 g as an average size by the end of the advanced nursing.