Category:Fungus and fungal diseases/Diagnosis of fungus

Diagnosis[edit]

Actively growing fungus (typically Saprolegnia and Achyla) in an aquarium is primary a sign of low quality aquarium conditions by the owner. It appears as fluffy white^* growths (Hyphae) on any surface in the aquarium looking a lot like a lump of cotton wool in fact.

This is probably why this fungus is often called The Cotton Wool Disease.

^*Note: the colour may turn from white to grey to reddish-brown if allowed to advance.

There is a disease which looks very similar to Cotton wool disease and this is actually a bacteria infection called Mouth fungus or Cotton Mouth Disease as it often appears on the mouth of fish. It is not a fungus, it is the bacteria Flexibactor columnaris. So to treat this you'll need a bacterial treatment specifically for this.

It is difficult to tell the two apart but generally F. columnaris has a coarser, more granular appearance and can be a dull grey-white than true fungus white.