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Hole In The head
Lateral Line Disease

Affected fish

Mainly cichlids, especially Discus, Oscars and Angelfish.


A parasite, Spironucleus vortens, which is found in the gut, is usually kept in check by the fishes immune system. If the fishes immune system is compromised, the parasite can multiply and cause damage to the gut wall affecting the fishes ability to digest food and obtain nutrients. Hole in the head or lateral line disease occurs when the parasites build up in the blood stream and collect along the lateral line, blocking blood vessels and causing tissue erosion.


Darkening of colour, wasting, reluctance to feed are common symptoms along with the more obvious erosion or pores which appear along the head and lateral line.


Good diet may have a factor in preventing the disease


Specific treatments are available for the problem, including many based on metronidazole (Flagyl)


A similar protozoan parasite, Hexamita, affects the same groups of fish in very similar ways, and hole-in-the-head and lateral line are often attributed to hexamita by mistake. Luckily, the treatments for both are the same so miss-diagnosis is not too much of a problem.

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