Ulcers on Goldfish and Koi: Aeromonas Infection and Treatment

Diagnosis

Red/white expanding sores on otherwise eating fish = Aeromonas hydrophila (ulcer disease). Common in spring when immune systems are low.

Treatment Protocol

1. KoiZyme (formerly Lymnozyme): Competitive exclusion bacteria that starve Aeromonas. Dose per label.
2. MelaFix: Natural antiseptic; helps minor lesions.
3. Pond salt: 0.1% (no plants) or 0.05% (with plants) for 2 weeks.
4. Water quality: Pristine—0 ammonia, 0 nitrite, stable pH.
5. Isolate severely affected fish for topical treatment (iodine swab + antibiotic injection if vet available).

Why Meds Failed Before

Over-the-counter "ulcer meds" often contain malachite green/formalin—ineffective against systemic Aeromonas and harmful to biofilter. KoiZyme targets the root cause.

Source

KoiZyme: koizyme.com