Coral diseases in aquaria and in nature

Abstract

Many reef coral diseases have been described affecting corals in the wild, several of which have been associated with causal agents based on experimental inoculation and testing of Koch’s postulates. In the aquarium industry, many coral diseases and pathologies are known from the grey literature but as yet these have not been systematically described and the relationship to known diseases in the wild is difficult to determine. There is therefore scope to aid the maintenance and husbandry of corals in aquaria by informing the field of the scientifically described wild diseases, if these can be reliably related. Conversely, since the main driver to identifying coral diseases in aquaria is to select an effective treatment, the lessons learnt by aquarists on which treatments work with particular syndromes provides invaluable evidence for determining the causal agents. Such treatments are not commonly sought by scientists working in the natural environment due the cost and potential environmental impacts of the treatments. Here we review both wild and aquarium diseases and attempt to relate the two. Many important aquarium diseases could not be reconciled to those in the wild. In one case, however, namely that of the ciliate Helicostoma sp. as a causal agent of brown jelly syndrome in aquarium corals, there may be similarities with pathogenic agents of the wild coral diseases, such as white syndrome and brown band syndrome. We propose that Helicostoma is actually a misnomer, but improved understanding of this pathogen and others could benefit both fields. Improved practices in aquarium maintenance and husbandry would also benefit natural environments by reducing the scale of wild harvest and improving the potential for coral culture, both for the aquarium industry and for rehabilitation programmes.