bacterial or physical · both tank

Popeye (Exophthalmia)

Popeye (exophthalmia) is the swelling of one or both eyes outward from the socket. Caused by bacterial infection, physical injury, or systemic disease.

Reviewed by the Fast Aquatics husbandry team · Updated May 2026
Severity: Moderate - eye damage can be permanent if untreated

Symptoms to look for

What causes it

Unilateral popeye = usually injury (rough handling, bumped on rocks). Bilateral popeye = systemic infection or poor water quality.

Treatment options

Multiple effective treatments exist. Pick based on your tank type, livestock sensitivity, and severity. Always treat in a separate quarantine/hospital tank - most medications are toxic to coral, invertebrates, and live rock biology.

Epsom salt. 1 tablespoon per 5 gallons in a hospital tank for 5-7 days. Reduces swelling. Combine with clean water and rest.
Kanaplex (Seachem). For bacterial popeye: full course in hospital tank for 5-7 days. Effective against gram-negative bacteria.

Prevention

Cover sharp rockwork, avoid chasing fish with nets, maintain pristine water quality.

Frequently asked questions

What does Popeye (Exophthalmia) look like?

One or both eyes bulging from socket. Cloudy or pus-filled eye. Eye injury or scratches.

What causes Popeye (Exophthalmia)?

Unilateral popeye = usually injury (rough handling, bumped on rocks). Bilateral popeye = systemic infection or poor water quality.

How is Popeye (Exophthalmia) treated?

Epsom salt: 1 tablespoon per 5 gallons in a hospital tank for 5-7 days. Reduces swelling. Combine with clean water and rest.

Can Popeye (Exophthalmia) be prevented?

Cover sharp rockwork, avoid chasing fish with nets, maintain pristine water quality.

How fatal is Popeye (Exophthalmia)?

Moderate - eye damage can be permanent if untreated

Should I treat in the display tank or quarantine?

Always treat in a separate quarantine or hospital tank. Most medications are toxic to coral, invertebrates, and live rock biology.

Related

Browse the full disease database for 45 aquarium conditions with treatment protocols, or check the care library for prevention-focused husbandry guides. Use our symptom matcher to rank likely diseases from observed signs, the water parameter checker to diagnose related water-quality issues, or the QT timeline calculator to plan a treatment schedule.