(Stop The) Fight Club

African cichlids are notorious for turning on each other, but can enrichment broker in a peace treaty? One college decided to look into it — with surprising results.

- Andrew Golley And Eleanor Chappell

Environmental enrichment for captive animals involves providing a variety of physical and mental stimuli to promote positive, natural behaviours, and to reduce the negative or ‘stereotypical’ behaviours. The approach is widely studied, and common with companion, zoo, public aquaria, and laboratory animals worldwide.

Stimuli may range from simple scatter feeds, to promote foraging behaviour in primates, birds, and hoof stock, through increasingly complex items, like papier mâché animals filled with meat for predatory cats, to puzzle boxes for octopus.

In aquaria, many of us provide enrichment as a matter of course, such as caves for dwarf cichlids, wood for some Loricariids, seaweed for surgeonfish, and rockwork for Rift Valley cichlids. All of these help fish to express natural behaviour, stay healthy, and in some cases, even breed successfully.

But is enrichment always a positive thing? Can it do more harm than good? For example, back in 1990 a study by McGregor and Ayling showed that providing laboratory mice with more varied cages dramatically increased aggression between individuals. These results were attributed to the fact that the enrichment added to the cages were ‘defendable’ resources.

Still, appropriate and safe environmental enrichment for captive animals, applied correctly, is almost universally considered a good thing, and is frequently listed as a factor when assessing animal welfare.

Experimenting for aggression

At Cornwall College, in Newquay, we have a pretty typical Malawi cichlid set-up. A 180 x 60 x 60cm display, plus sump, provides approximately 900 l and includes a collection of about 60 mbuna, made up of Yellow labs, Labidochromis caeruleus; Red zebras, Maylandia estherae; Cynotilapia spp., Melanochromis spp., and a Synodontis eupterus catfish.