Malawi cichlid reproduction differs in aquaria

The reproductive behaviour of a Malawian haplochromine cichlid is different in first generation fish raised in aquaria.

Phillip Lobel of Boston University and Jennifer Ripley of West Virginia University studied the spawning behaviour of Tramitochromis intermedius in Lake Malawi and in first generation offspring kept in aquaria and found some interesting differences between the two groups.

In wild fish, spawning peaked at midday at the height of the light cycle, whereas in captivity, spawning occured at any time.

Lobel and Ripley suggest that this spawning photoperiodicity might have something to do with predation in the wild, while in captivity it could be due to a lack of environmental cues, or the tendency for smaller males to spawn opportunistically with females.

Like the other cichlids in this group, male T. intermedius build very large raised circular nests in the sand called bowers, which are used as spawning sites and tools to attract females. The females are maternal mouthbrooders and hold the developing eggs and larvae in their mouths for nearly a month without feeding.

Ripley and Lobel suggest that the circling behaviour used by males during the courtship process might be used to indicate dominance, with the most dominant males performing much larger circles of their bower than submissive fish nearby.

For more details see the paper: Ripley, JL and PS Lobel (2005) - Reproductive behaviour of the Lake Malawi cichlid fish, Tramitochromis intermedius. Environmental Biology of Fishes, Vol. 73., Number 2, 171-180.