Hole-in-the-Head Syndrome (HITH), also known as Freshwater Head and Lateral Line Erosion (FHLLE), is an important syndrome which affects primarily gouramis, angelfish, discus, oscars and large South American cichlids. HITH can also occur in saltwater fish and is known as Marine Hole-in-the-Head Syndrome and also as Marine Head and Lateral Line Erosion (MHLLE). HITH lesions are most prevalent on the fish’s head, though they may appear on the fish’s flanks, following the lateral lines down the body. Fish with lesions can behave normally for quite a long time, but eventually they will become sluggish, lose their appetite and become hollow bellied.
An oscar has spots on its’ head called sensory pits, which are a series of fluid filled sacs with tiny hairs that sense vibrations and convert them to electrical impulses. Both the sensory pits and the lateral lines are responsible for a fish’s positional sense in the water. The sensory pits look like little pin holes, generally arranged in a cluster. Continue reading →