Hexamita (Hole-in-the-Head)

Hexamita is a protozoan flagellate that colonises the intestinal tract. Under stress or poor water quality it migrates and causes the characteristic pits along the head and lateral line, often called “hole-in-the-head” (HITH) or “head and lateral line erosion” (HLLE).

Causes

Poor water quality, especially elevated nitrates (>40 ppm). Activated-carbon over-use, vitamin deficiency in the diet, and stress are all contributing factors. Cichlids — particularly oscars and discus — are most affected.

Treatment

Metronidazole at 250 mg per 10 gallons every other day for 3 doses, combined with a 50% water change. Soaking food in metronidazole solution (100 mg / 1 oz food) is the most effective delivery for fish still eating. Improve water quality concurrently: nitrates below 10 ppm, fresh activated carbon, and varied diet.

Recommended medications

Intestinal flagellate parasite causing pitted lesions on the head and lateral line, especially in cichlids and discus. Often…

Prevention

Keep nitrates below 20 ppm via regular water changes. Feed a varied, vitamin-rich diet. Avoid running heavy activated carbon long-term — it can strip trace elements.

Frequently asked questions

Will the holes in my fish's head ever heal?

The disease is curable but the scars are usually permanent. The lesions close and re-pigment partially but the depressions remain.

Can hexamita spread to other fish?

Yes, but most healthy fish carry low levels without symptoms. Outbreaks signal an environmental problem more than a contagion problem.

Freshwater Tropical