The bulk format of API's tea-tree based freshwater remedy, for fin and tail rot, open wounds and abrasions, eye cloud, pop-eye, body slime and mouth fungus. It treats the infection and supports regrowth of damaged fins and tissue, usually over about a week, without harming the biological filter or clouding the water.
"Professional Strength" describes the pack, not the formula. The active ingredient is cajuput oil at 1%, the same concentration as the small retail bottles — it is a 1.89 litre container for people dosing large tanks or several at once, not a stronger version. It is also the freshwater product: ponds want Pond Melafix, which is a different, more concentrated formulation, and marine tanks want Marine Melafix.
Dosage
- 5 ml (1 teaspoon) per 10 US gallons (about 38 litres)
- Sick or injured fish: dose daily for 7 days, then change 25% of the water
- New arrivals: dose daily for 3 days
Before you dose
Take activated carbon out of the filter first — carbon adsorbs the remedy and will strip it back out of the water. Aquarium use only; keep out of reach of children.
Smaller bottles: API Melafix. For fungal infections, Pimafix.

