Hydrogen Peroxide in Fish Treatment: FDA Label Dosing and Safety
How hydrogen peroxide (35% PEROX-AID), an FDA-approved aquaculture drug, treats egg fungus, bacterial gill disease and columnaris, with label mg/L doses and a 0-day withdrawal.
Overview
Hydrogen peroxide (H2O2) is the simplest peroxide and a strong oxidizing agent that decomposes into water and oxygen (2 H2O2 to 2 H2O + O2). In aquaculture the FDA-approved product 35% PEROX-AID (NADA 141-255) is classified as an external disinfectant, applied by immersion. Its effect is at the topical site, so the concentration, exposure time and water conditions determine efficacy.
What it treats
Per the FDA approval, 35% PEROX-AID is approved to control mortality in freshwater-reared finfish eggs due to saprolegniasis (water mold), in freshwater-reared salmonids due to bacterial gill disease associated with Flavobacterium branchiophilum, and in freshwater-reared coolwater finfish and channel catfish due to external columnaris disease associated with Flavobacterium columnare (Flexibacter columnaris).
Administration and dosing
The following doses are taken directly from the FDA 35% PEROX-AID label. All are given by immersion (continuous-flow or static bath); an initial bioassay on a small number of fish is recommended before treating the whole group.
| Indication / group | Dose | Regimen |
|---|---|---|
| Eggs, cold/coolwater species (saprolegniasis) | 500 to 1000 mg/L for 15 minutes | Continuous flow, once/day on consecutive or alternate days until hatch |
| Eggs, warmwater species (saprolegniasis) | 750 to 1000 mg/L for 15 minutes | Continuous flow, once/day until hatch |
| Salmonids (bacterial gill disease) | 100 mg/L for 30 min, or 50 to 100 mg/L for 60 min | Once/day on alternate days for three treatments |
| Coolwater finfish (except northern pike & paddlefish) and channel catfish (columnaris) | 50 to 75 mg/L for 60 minutes | Once/day on alternate days for three treatments |
| Coolwater finfish fry and channel catfish fry | 50 mg/L for 60 minutes | Once/day on alternate days for three treatments |
The FDA label notes that the product should be used with caution on walleye, and that an initial bioassay is recommended for the affected group before full treatment.
Safety and precautions
Hydrogen peroxide is unstable, decomposing faster with heat, light and catalysts, so its toxicity to fish rises with temperature and a margin must be kept at warmer water temperatures. Because it releases oxygen as it breaks down, treatment can temporarily raise dissolved oxygen, but spent solution and stressed gills still warrant close observation. The concentrated 35% stock is corrosive and a strong oxidizer; operators handle it with appropriate protective equipment, and it is stored cool and away from light and incompatible materials.
Regulatory status and withdrawal
In the United States 35% PEROX-AID is FDA-approved and sold over the counter for the indications above. There is no required withdrawal time after treatment with this product (a 0-day withdrawal). Legal status and approved uses vary by country and apply to food fish; consult a fish-health veterinarian and the current label before use.