Hexamita (Hole in Head) guide for aquarists. Symptoms, treatment protocol, prevention, and when to escalate.
Hexamita (Hole in Head) TL;DR
Affects: cichlids, discus, marine angelfish · Symptoms: pitted lesions on head, white stringy feces
Treatment: Metronidazole in food + water, address water quality + activated carbon
What is hexamita (hole in head)
Hexamita (Hole in Head) is a common aquarium disease/pest affecting cichlids, discus, marine angelfish. Recognizing it early and treating quickly is the difference between losing a single fish and losing an entire tank.
Symptoms to watch for
pitted lesions on head, white stringy feces. Watch for behavior changes (reclusive, refusing food, color loss) as early warning signs - even before visible symptoms appear, fish stress patterns indicate something is wrong.
Treatment protocol
Metronidazole in food + water, address water quality + activated carbon. Always treat in a separate hospital tank to protect invertebrates, coral, and beneficial bacteria. Follow medication protocol exactly - underdosing produces resistance, overdosing creates new problems.
Prevention
Quarantine new fish for 4-6 weeks before adding to your display tank. Stable parameters + appropriate stocking + adequate filtration prevent the chronic stress that makes fish susceptible to disease in the first place.
When to escalate
If symptoms persist beyond expected treatment duration, parasites/symptoms reappear after treatment, or the disease spreads despite isolation, escalate to a fish-specific veterinarian or experienced reef keeper. Aquatic veterinarians offer prescription medications (chloroquine, levamisole) not available over-the-counter.
Hexamita (Hole in Head) FAQ
Is hexamita (hole in head) contagious?
Yes - most fish diseases spread via water column or direct contact. Isolate infected fish in a hospital tank.
Can I treat in the display tank?
For most diseases - no. Copper kills inverts, antibiotics destroy beneficial bacteria. Always treat in a hospital tank.