Fully grown females in captivity can reach a length of between five and six inches while males tend to be marginally smaller.

A very peaceful shoaling species, M. argenteus can be skittish and timid if left without any kind of shelter, and if kept in isolation they tend to become reclusive.

They will nibble at sliced cucumber and show considerable interest in shelled peas and carrots, boiled potato and small chunks of fresh and tinned fruit.

They scatter eggs among fine-leaved plants as well as directly on to the substrate during a characteristic, side-by-side, shimmying courtship ritual.

The idea is that the eggs fall between the gaps in the marbles where they can develop in peace: other fish can't get to them during that vulnerable period and when the fry do eventually rise they are equipped with a chance of dodging predators.