Abstract

Bagrus meridionalis (Bagridae; locally called Kampango) is a large substrate-spawning catfish endemic to Lake Malaŵi that exhibits bi-parental care and spawns primarily in the wet season from January to March. The female feeds her young trophic (unfertilized) eggs; the male orally collects offsite benthic organisms, which he brings back to feed the brood. While doing underwater videography in the lake, we observed evidence for brood parasitism of four Kampango nests by the most common clariid catfish in Lake Malaŵi, the endemic Bathyclarias nyasensis (locally called Bombe). Parasitized Kampango nests held Bombe young almost exclusively, and these were protected by Kampango adults until they exceeded 100 mm SL. We found that female and male Kampango fed the Bombe juveniles with trophic eggs and macroinvertebrates, respectively, as they do their own young. These observations represent a sophisticated example of cuckoo behavior in fishes.