Hole-in-the-head disease: (n.) Most often affecting saltwater species and freshwater cichlids, head and lateral line erosion (HLLE) is a condition that causes skin, scale and tissue loss in the head region and/or along the lateral line sensory system or flanks of fish. The lesions first appear as pinpoints that grow in size and number; these lesions lack pigmentation. Cause is unknown, though stress, vitamin deficiencies, the parasite Hexamita and poor water quality are thought to play a role; untreated cases can be disfiguring or fatal.
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