Shell dweller

The terms shell dwellers or shelldwellers, shell-breeding, or ostracophil are descriptive terms for cichlid fish that use the empty shells of aquatic snails as sites for breeding and shelter. The terms have no taxonomic basis, although most shell-dwelling cichlids are from Lake Tanganyikas lamprologine lineage. Many shell dwelling cichlids are popular with fishkeepings and are frequently kept in aquaria.

In Lake Tanganyika the shells inhabited are from the genus Neothauma, while shells used by Pseudotropheus lanisticola in Lake Malawi are from genus Lanistes.

Around 24 species of lamprologine cichlids use abandoned shells for shelter and breeding in Lake Tanganyika. Most, however, are not obligate shell-breeding cichlids and will spawn in other caves or crevices.

There are several groups the shell dwellers can be placed into:

Shell dwellers are found throughout Lake Tanganyika, along the coasts of Zambia, Democratic Republic of Congo, Burundi and Tanzania.

Shell dwellers are carnivores that primarily feed on zooplankton and other microscopic and near-microscopic foods.

Cichlids' distinctive pharyngeal teeth, in the throat of the fish, are present in shell dwellers, though small. Armed with those and the usual teeth along with the typical dissolving qualities of water shell dwellers can eat a variety of foods in the wild and in captivity. Many species have been known to pull small snails from their shells to eat, to catch and devour the fry of other fish, and to go after small crustaceans.

As with other cichlids they protect their young, and the distinctive shell-dwelling provides them with a defensible nursery.

Generally eggs are laid by the female within the shell and fertilized as she lays them or immediately after by the male.

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