![]() ![]() The resulting ephyrae should be removed from the polyp tank to prevent them being eaten by the polyps and transferred to a similar set-up, the open-ended air line helping to move the juveniles and keep the Artemia in suspension. Strobilation in Aurelia occurs after prolonged changes in temperature and some success has been achieved by adding iodine to the culture water, although different ‘strains’ of Aurelia may have different triggers for strobilation. Add shells and other objects to which they can attach. If maintained at a constant temperature and fed sufficiently, the polyps will reproduce asexually by 'budding' so a small number can give rise to a carpet. Filtration is unnecessary, with water quality maintained through regular syphoning of detritus and subsequent water changes.Įnsure that excessive feeding doesn’t allow hydroids to take over the tank. Polyps can be maintained simply in a small, bare aquarium with open-ended air line fixed to the base to circulate food - Artemia nauplii, preferably decapsulated to prevent ingestion of the indigestible cysts - and provide gas exchange. Life spans of over four years for individual Aurelia medusae have been reported, although two is a more usual. The ephyrae become part of the plankton where they grow into medusae - the reproductive and dispersal stage - and the life cycle turns full circle. This eventually becomes a strobila - each one producing around 15 flattened discs and each of these being an ephyra, a juvenile jellyfish with a star-like appearance and eight bifid ('split') arms released in a process called strobilation. Adult medusae reproduce sexually to produce a planula larva which anchors itself to a substrate before becoming an anemone-like scyphistoma -the polyp stage – similar to those of corals, to which jellyfish are related. The familiar 'jellyfish' (the 'medusa' stage) is only a part of the life cycle of Aurelia, which is seemingly rather complex for such primitive, simple creatures. There is debate about the taxonomy of the genus Aurelia, but we consider it a pretty cosmopolitan group of closely-related populations. Many aquarium jelly tanks are more correctly referred to as pseudokreisels as they 'borrow' elements from the 'true' kreisel design but modified for better viewing.Īurelia aurita is a species of scyphozoan ('true') jellyfish with a more or less worldwide distribution. The aim is to produce a gentle, flowing water motion in which the delicate jellies and their food can be suspended. Success with keeping jellies was due to the development of the kreisel tank (from the German for ‘merry-go-round’), which was originally designed to keep gelatinous planktonic animals alive on research ships and in laboratories. However, pioneering work in the early 1990s at California’s Monterey Bay Aquarium, along with data gathered in Japanese aquariums, succeeded in maintaining a variety of species, starting with the Moon jelly (Aurelia aurita) which is still the most common jellyfish in captivity. Until recently it was thought impossible to keep pelagic (open ocean) jellyfish for any length of time in captivity - standard aquarium conditions proving totally unsuitable. Keeping jellyfish is a relatively new branch of aquarium science. They remain, however, a relatively common sight in public aquaria and, with some commercially available systems now appearing, how viable do they now seem for domestic tanks? However, this idea is never sustained and jellies have failed to become as popular as predicted. David Wolfenden wonders if jellyfish are about to become a home hobby favourite.Įvery now and then, a fair number of hobbyists become interested in keeping jellyfish at home. Complicated life cycles ultimately create these simple but beautiful sea creatures.
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