Fin Rot
Bacterial (and sometimes fungal) infection affecting fins and tail. Usually secondary to stress or poor water quality. Fins appear to disintegrate from the edges.
Check these symptoms in your tankSymptoms of Fin Rot
- Ragged or fraying fins
- Discolored fin edges (brown/red)
- Lethargic / hiding more than usual
- Refusing to eat
- Faded or lost color
How to treat Fin Rot
- Perform 25–30% water change immediately
- Test and correct water parameters, fin rot rarely occurs in pristine water
- Mild cases: aquarium salt + clean water may be sufficient
- Moderate/severe: API Melafix or Kanaplex (antibacterial)
- Remove aggressive tank mates if fin-nipping is the cause
How to prevent it
- Maintain excellent water quality with regular partial water changes
- Avoid overcrowding and aggressive tank mates
- Provide a balanced diet and reduce stress
Conditions with similar symptoms
Open sores or ulcers on the body caused by Aeromonas or Pseudomonas bacteria. Often secondary to wounds, handling stress, or poor water quality. Ulcers can deepen rapidly and become life-threatening.
Fluffy white or gray cotton-like patches on body, fins, or around mouth. Often secondary to wounds, fin rot, or poor water quality.
Bacterial infection causing fluid buildup behind the eye, making it protrude. Usually affects one eye. Bilateral pop-eye is more serious and often indicates an internal systemic infection.
Not sure? Use the symptom checker
Many fish diseases look alike. Pick the symptoms you see in the free fish disease checker to compare likely causes, or scan a test strip to rule out a water problem first.