CCA – Ad Konings – September 2007

CCA’s September 8th meeting probably drew a record crowd, and for good reason; Ad Konings, author of over 30 books and expert of African cichlids traveled from his home in Texas to speak to us about the feeding behavior and relationships of Lake Malawian cichlids. There were quite a few items up for auction, including some of Ad’s books and fish traded from another club via a fish swap. Ad’s talk was fascinating, and included countless video clips demonstrating each type of feed behavior found in the lake cichlids.

To summarize his talk, he says that all cichlids in Lake Malawi are either algae eaters (herbivores), invertebrate eaters (carnivores), or fish eaters (piscivores). Inside of each of these groupings, there are a number of specializations describing exactly how they feed. For example, within the algae eaters, Tropheops tropheops is a “shaker,” which means that they lock their jaws on strands of algae, and shake their body to rip off whatever algae will detach from rocks. Others, such as Pseudotropheus sp. “elongatus aggressive” have specialized jaws with teeth protruding outward to be able to scrape algae completely from the rocks. Then, Hemitilapia oxyrhynchus is considered a “leaf stripper” which means that they affix their jaws on strands of Vallisenaria and then slide the leaf through their jaws, stripping it of any algae.

Copyright, Ad Konings. Presented at CCA September 2007 meeting.

The carnivores are even more specialized. Pseudotropheus sp. ‘williamsi’ leap from the water to catch flies congregating overhead in still patches of air surrounding large rock outcrops. Protomelas pleurotaenia blows detritus from the substrate, hoping to unearth hidden insects and invertebrates to feed upon. Meanwhile, cyrtocara moori will follow other earth-eating fish, and feed on any extra food in the clouds of detritus that they create. Mylochromis epichorialis only feeds on small crabs, while Aulonocara stuartgranti has a specialized holes in their jaw allowing it to use sonar to pinpoint insects underneath the substrate to prey upon.

Copyright, Ad Konings. Presented at CCA September 2007 meeting.

Finally, the fish eating cichlids find ways to prey upon other fish for their food. Metriaclima pursus cleans scales of other fish, often where the other fish willingly allow the Metriaclima to work. Caprichromis liemi manages to dart toward other fish, ripping aquatic lice from their throat for their meals. Genyochromis mento is a fin biter that has many color morphs throughout the lake to match the color patterns of its prey in each area. That allows the fish to get close to its prey, and nip patches of finage from unsuspecting fish. Nimbochromis livingstonii plays dead on the lake floor near other fish’s fry, waiting for them to move close enough for attack. Sciaenochromis fryeri actually imitates algae-eating behavior to get close enough to their target prey.

Copyright, Ad Konings. Presented at CCA September 2007 meeting.

This is only a subset of the information that Ad delivered during his presentation. It’s really fascinating how specialized the fish in Lake Malawi are. In Lake Malawi there are over 884 species of cichlids. That’s more than the 800 species of freshwater fish in all of North America. With so many species in a single lake, each has adapted to best be able to survive in their own micro-environment. A fascinating talk!