Ubat Biru Ikan (Methylene Blue): How to Use It Safely for Fish

Ubat biru ikan is the everyday Malaysian name for methylene blue, a dark blue dye that has been used in fishkeeping for decades. It's mild, cheap and easy to find. It's useful for fungus on eggs and wounds, some external parasites, and as first aid for fish suffering from nitrite or ammonia poisoning. But it stains almost everything blue and can kill the good bacteria in your filter, so it works best in a separate hospital tank or a short bath, not poured into a planted display tank.

What Ubat Biru Treats

Use	How well it works	Notes
Egg fungus	Very good	The most common use. Protects eggs from fungus in a hatching container.
Fungus on fish (kulat)	Good for mild cases	See our kulat pada ikan guide
Nitrite / ammonia poisoning	Useful first aid	Helps blood carry oxygen when nitrite has damaged it; the water still needs fixing
Some external parasites	Mild	Used alongside or before stronger treatments
White spot	Mild	Gentle option in small tanks; stronger medicines usually work faster. See white spot treatment
Transport and handling stress	Supportive	Some keepers add a small amount to bags or holding tubs
Internal bacterial infections	Not effective	Use a proper antibacterial medicine

What About "Garam Ikan Biru"?

Some shops sell blue-coloured salt or "garam ikan biru". Read the label: some contain methylene blue mixed with salt, others are just tinted salt. If you want to control each one separately, buy plain garam ikan and plain methylene blue.

How to Use Ubat Biru Ikan

Check the bottle's strength

Methylene blue is sold in different concentrations. One brand's "drops per litre" can be very different from another's. Always follow the label of the bottle you have. Don't follow a dose from a forum unless it's for the same product.

Hospital tank method (most common)

1. Fill a hospital tank or plastic container with water from the main tank, or new water treated with anti klorin.
2. Add an air stone. Don't run a filter with carbon, since carbon removes the dye.
3. Dose as the label says for the actual water volume. The water should turn clearly blue, but you should still see the fish.
4. Keep the fish in for the period on the label, often several days, with partial water changes and re-dosing as directed.
5. Keep the container out of direct sunlight. Light breaks down methylene blue faster.

Short bath (dip) method

Some labels give a stronger concentration for a short bath, from a few minutes to an hour. Watch the fish the whole time and return it to clean water if it shows distress.

For fish eggs

• Move eggs (or the slate, leaf or spawning mop they're on) into a small container with water from the breeding tank.
• Add methylene blue at the egg dose on the label, usually enough to turn the water light to medium blue.
• Add gentle aeration.
• Remove white, fuzzy eggs as they appear.
• Many keepers do a partial change to reduce the blue once fry hatch, since fry are more sensitive.

This is common practice with ikan manfish (angelfish), goldfish and other egg-scatterers. For bettas, keep the bubble nest undisturbed in the breeding tank unless eggs are clearly fungused.

Side Effects and Cautions

It stains

Methylene blue stains silicone seals, plastic, decor, sponges, airline tubing, hands and clothes. Stains on silicone can last a long time. Use a separate container you don't mind turning blue, and wear gloves.

It harms filter bacteria

The dye can disrupt the beneficial bacteria that break down ammonia and nitrite. In a main tank, this can cause an ammonia spike after treatment. That's another reason to use a hospital tank.

It's hard on plants and shrimp

Live plants can be damaged, and shrimp and snails are more sensitive. Move them out or treat fish elsewhere.

Combining with other medicine

Methylene blue is often combined with garam ikan in a hospital tank. Don't mix it with other medicines unless the labels say it's safe.

Removing it afterwards

Do several water changes and add fresh activated carbon to the filter to pull out remaining dye. The water will slowly go back to clear.

Malaysian Tips

• Warm water (27–31°C) means fish use more oxygen. Always add an air stone or air pump during treatment.
• Small containers heat up fast near windows. Keep hospital tubs in a shaded, stable spot.
• Measure volume properly. A tub labelled 20 litres often holds less when filled to a safe level. Our tank size guide explains how to calculate litres.
• Store the bottle away from sunlight and out of reach of children.

What to Keep with Ubat Biru

Methylene blue belongs in a basic home first-aid kit, together with aquarium salt, anti klorin, a test kit and a spare container. Our ubat ikan sakit first-aid kit guide explains what to keep and why.

FAQ

Ubat biru ikan untuk apa?

Ubat biru (methylene blue) biasanya digunakan untuk mencegah kulat pada telur ikan, merawat kulat ringan dan luka, serta sebagai bantuan awal untuk ikan yang keracunan nitrit. Ia kurang berkesan untuk jangkitan bakteria dalaman.

Boleh letak ubat biru dalam akuarium utama?

Tidak digalakkan. Ubat biru boleh mengotorkan silikon dan hiasan, merosakkan pokok dan membunuh bakteria baik dalam penapis. Lebih selamat guna dalam bekas atau akuarium rawatan yang berasingan.

How much methylene blue should I use?

It depends on the bottle's concentration, so follow the label for your product and dose for the real water volume. The water should be clearly blue but not so dark you can't see the fish.

Is methylene blue safe for bettas?

Yes, when used at the label dose in a separate container. Many betta keepers use it for fin damage and fungus. Keep the container shaded and change water as directed.

How do I remove methylene blue stains?

From water, use water changes and fresh activated carbon. From silicone and plastic, stains may be permanent. From skin, soap and time. Use gloves next time.

---

Find methylene blue and other ubat ikan, water conditioners and air pumps from Malaysian sellers on FishyHub.