Glossary: head and lateral line erosion
Severe physical condition relatively common to certain fishes in captivity and also known as hole-in-the-head. Sometimes attributed to protozoan parasites of the genus Hexamita or an autoimmune disorder though these theories remains unconfirmed. Certainly associated with and exacerbated by poor water quality and/or nutrition, however. Initially manifests itself as small lesions, normally on the head of an affected individual, but may also extend along the lateral line and into the unpaired fins. If left unchecked these lesions can develop into larger, whitish pits and the condition may prove fatal. Often abbreviated to HLLE and similar to, but not analagous with, neuromastic pitting. Does not appear to occur in nature.