API Betta Fix

• Dosed in units that suit a betta tank – the label gives a rate for a 1 litre container, not just for a 38 litre aquarium, so you are not trying to measure a fifth of a millilitre.
• 0.2% melaleuca oil – one fifth the concentrate strength of API Melafix, pre-diluted so a small overdose in a small volume is less likely.
• Stated safe with snails and shrimp – API states BettaFix is safe with invertebrates such as snails and shrimps.
• Does not harm the biological filter – API states it will not harm the biological filter or aquarium plants, so a filtered betta tank can be treated in place.
• Seven-day course, then stop – the label sets a defined end point and a water change, rather than open-ended dosing.

Transcribed from API's registered label. Repeat the dose daily for up to seven days, then make a water change.

That works out to roughly 0.66 mL per litre of water, whichever measure you start from.

A single dose is not the useful number here, because BettaFix is dosed daily for a week. Worked out as complete seven-day courses:

The practical limit is around 10 litres. Above that, a 50 mL bottle of BettaFix cannot finish a single course, and the concentrate is the sensible buy instead.

These are the same active ingredient at different strengths, and the difference is genuinely one of packaging rather than potency. Both labels work out to about the same amount of melaleuca oil in the water once dosed.

So BettaFix is not a weaker treatment. It is the same treatment pre-diluted, so that a measurable dose exists for a volume of water where a drop either way of the concentrate would matter. If your betta lives in a 60 litre planted tank, API Melafix is the cheaper and more practical choice.

Transcribed from API's registered label, checked 7 August 2026.

API does not declare the inactive ingredients for BettaFix on the label, so we cannot list them.

Suitable for:

• Betta bowls, jars and tanks up to about 10 litres
• Tanks housing snails or shrimp, which API states are unaffected
• Planted betta tanks, which API states are unaffected
• Treating in the display tank, since the biological filter is not harmed

Not suitable for:

• Aquariums above about 10 litres, where one 50 mL bottle cannot complete a course
• Open-ended dosing. The label stops at seven days and a water change
• Replacing a diagnosis. Torn fins caused by a sharp ornament, a tank mate or poor water quality will keep recurring until the cause is fixed
• Any fish intended for human consumption

Complete the seven days, then make a water change as the label directs. If the signs have not improved, stop and reassess rather than starting straight into another course. Check ammonia, nitrite and temperature first, because damaged fins very often trace back to water quality or a chill rather than to an infection that a remedy alone will resolve.

API's label carries no instruction to remove activated carbon. If you run carbon and want to be sure the dose stays in the water, take it out for the seven days and refit fresh carbon at the final water change.

• Harmful if swallowed. Causes serious eye irritation. Causes skin irritation.
• For animal treatment only. Not for human consumption, and not for treating fish intended for human consumption.
• Keep out of reach of children.
• Store below 38 degrees C, which in a Queensland summer means indoors rather than in a garage or shed.

• API Melafix – the same active at 1.0%, for aquariums above about 20 litres.
• API Pimafix – API's companion remedy, indicated for fungal signs rather than bacterial.
• API Freshwater Master Multi Test Kit 5 in 1 – rules out the ammonia or nitrite problem that causes most fin damage in small tanks.
• API Betta Water Conditioner 50ml – dechlorinates the replacement water for the post-course change.
• API Aquarium Salt – freshwater tonic salt, often used alongside a course in a quarantine tank.
• Marina Floating Glass Thermometer – bettas held below about 24 degrees C get sick, and an unheated bowl is a common cause.

This is a consumable remedy, so no manufacturer warranty period applies. Your rights under the Australian Consumer Law are unaffected: if the product is faulty, unsafe or not as described, you are entitled to a remedy. Ships as standard freight.

How much API BettaFix do I use in a 4 litre betta tank?

About 2.6 mL a day, following API's rate of half a teaspoon (2.5 mL) per US gallon (3.8 L). Repeat daily for up to seven days, then make a water change. A 50 mL bottle covers roughly two full courses at that volume.

Is BettaFix just watered-down Melafix?

Effectively yes, and that is the point. BettaFix is 0.2% melaleuca oil dosed at 2.5 mL per 3.8 L; Melafix is 1.0% dosed at 5 mL per 38 L. Both land at roughly 1.3 mg of melaleuca oil per litre of tank water. BettaFix exists so a measurable dose is available for a container too small to dose the concentrate accurately.

Is API BettaFix safe with shrimp and snails?

API states that BettaFix is safe with invertebrates such as snails and shrimps, and that it will not harm the biological filter or aquarium plants. That makes it usable in a planted betta tank without moving the fish out.

Do I need to remove activated carbon while dosing?

API's BettaFix label gives no instruction to remove carbon. If you run carbon and want certainty that the dose stays in the water, remove it for the seven days and fit fresh carbon at the water change that ends the course.

What if my betta's fins have not improved after seven days?

Stop at seven days and make the water change the label directs, then look for a cause rather than re-dosing indefinitely. Test ammonia and nitrite, check the temperature, and check the tank for sharp ornaments or an aggressive tank mate. Persistent or worsening signs are worth a consult rather than a second bottle.

Can I use BettaFix in a saltwater tank?

No. BettaFix is a freshwater product for bettas. API sells a separate Marine Melafix formulation for saltwater aquariums.