Aquasonic Formalin/Malachite Solution 250mL – White Spot Treatment

Aquasonic Formalin/Malachite Solution 250mL is an aquarium fish medication formulated to help treat freshwater white spot (Ich), susceptible external parasites and certain fungal infections. Combining formalin and malachite green, this copper-free treatment is designed to help control organisms affecting the skin, fins and gills of ornamental freshwater fish.

White spot is one of the most common diseases affecting aquarium fish and can spread rapidly if left untreated. Affected fish may develop small white spots, rub against decorations, clamp their fins or experience breathing difficulties.

The larger 250mL bottle is a practical choice for medium to large freshwater aquariums, multiple fish tanks and quarantine systems requiring a complete treatment course.

Why Choose Aquasonic Formalin/Malachite?

• White spot treatment: Helps control freshwater Ich caused by Ichthyophthirius multifiliis.
• Targets external parasites: Formulated for susceptible protozoan parasites affecting fish skin and gills.
• Fungal treatment support: Can assist with certain external fungal and water mould infections.
• Helps manage cloudy or slimy skin: Suitable for certain external disease conditions associated with excess mucus or skin irritation.
• Copper-free formula: Uses formalin and malachite green rather than copper sulphate.
• Economical 250mL bottle: Treats approximately 1,000 litres per standard application.
• Suitable for larger aquariums: Provides sufficient medication for multiple doses or larger freshwater treatment systems.

What Does Aquasonic Formalin/Malachite Treat?

White Spot Disease (Ich)

Freshwater white spot is caused by the parasite Ichthyophthirius multifiliis. It typically appears as small white spots resembling grains of salt on the fish's body and fins.

Other symptoms may include:

• Scratching or rubbing against gravel and decorations.
• Clamped fins and reduced swimming activity.
• Rapid breathing or irritation around the gills.
• Loss of appetite or unusual hiding behaviour.
• Small white spots on the body, fins or gill area.

White spot parasites have several developmental stages. Treatment is most effective against susceptible free-living stages, making correct dosing and an appropriate treatment schedule important.

External Protozoan Parasites

Aquasonic Formalin/Malachite may also assist in controlling certain external protozoan parasites that irritate the skin and gills.

Symptoms can include flashing, excessive mucus production, clamped fins and breathing difficulties. Because these symptoms can also indicate poor water quality or other diseases, accurate diagnosis is important.

External Fungal Infections

The combination of formalin and malachite green may help control susceptible fungal organisms and water moulds affecting ornamental fish.

Fungal infections sometimes develop around damaged tissue and can appear as white or grey cotton-like growths.

Important: Not every white patch or case of fin damage is caused by fungus or white spot. Bacterial infections and other parasites can produce similar symptoms and may require different medication.

How Aquasonic Formalin/Malachite Works

Aquasonic Formalin/Malachite combines two established ingredients used in ornamental fish treatments.

• Formalin: A formaldehyde-based solution used against susceptible external parasites and certain fungal organisms.
• Malachite green: A dye-based treatment with activity against certain external parasites and fungal organisms.

Together, these ingredients help control susceptible organisms affecting fish skin and gills.

Because formalin can affect oxygen availability and both ingredients may be harmful to sensitive fish and invertebrates, careful dosing and strong aeration are essential.

How to Use Aquasonic Formalin/Malachite Solution

Before treatment, confirm that your fish are showing symptoms consistent with a condition for which this medication is appropriate.

1. Calculate the actual aquarium water volume, allowing for gravel, decorations and equipment.
2. Check ammonia, nitrite, temperature and other relevant water parameters.
3. Remove activated carbon from the filter while maintaining biological filtration.
4. Turn off UV sterilisation during medication if directed by the product label.
5. Increase aeration to maintain adequate dissolved oxygen.
6. Measure the correct amount of medication for your aquarium.
7. Add the treatment according to the directions on the supplied bottle.
8. Monitor fish closely throughout treatment and follow the labelled repeat-treatment schedule.

Recommended Dosage

• Standard freshwater dosage: 5mL per 20 litres of aquarium water.
• Sensitive fish dosage: 5mL per 40 litres for tetras, juvenile fish and scaleless species such as loaches, where specified by the manufacturer.
• Repeat treatment: Follow the schedule printed on the supplied bottle.
• Standard coverage: Approximately 1,000 litres per application.
• Reduced-dose coverage: Approximately 2,000 litres per application.

At the standard dosage, a four-day course using one application per day requires 20mL per 20 litres. A 250mL bottle would therefore provide enough medication for approximately 250 litres across that four-day course.

Important: Published Australian instructions differ regarding treatment frequency. Follow the directions on your actual product label rather than combining instructions from different treatment schedules.

Important Treatment Precautions

• Freshwater fish: Intended for appropriate freshwater ornamental fish treatment.
• Sensitive fish: Tetras, juvenile fish, loaches and other scaleless fish may require reduced dosing or an alternative treatment.
• Shrimp and snails: Do not use in aquariums containing ornamental shrimp, snails or other sensitive invertebrates.
• Marine aquariums: Do not assume suitability for marine fish or reef systems without appropriate manufacturer instructions.
• Aeration: Maintain strong aeration throughout treatment. Formalin can reduce available dissolved oxygen.
• Activated carbon: Remove carbon filtration during medication.
• Temperature: Avoid raising aquarium temperature beyond the tolerance of the species being treated.
• Overdosing: Never exceed the recommended treatment dosage.
• Staining: Malachite green may stain silicone, clothing, aquarium equipment and surrounding surfaces.
• Handling: Formalin contains formaldehyde, a hazardous chemical. Avoid inhaling vapours and contact with skin and eyes.
• Storage: Store below 30 degrees Celsius, away from children and pets.
• Food fish: Not for use on fish intended for human consumption.

For heavily planted aquariums, sensitive fish or tanks containing invertebrates, a separate hospital aquarium may be more appropriate after confirming treatment compatibility.

If symptoms are severe, rapidly worsening or difficult to identify, seek advice from an aquatic veterinarian.

Active Ingredients

• Formalin: Formaldehyde-based solution.
• Malachite green: Antiparasitic and antifungal dye.

Australian product information references a 37% formaldehyde preparation used in the formulation. This should not be interpreted as the final formaldehyde concentration of the bottled medication. Always refer to the current product label.

Product Specifications

• Brand: Aquasonic
• Product: Formalin/Malachite Solution
• Volume: 250mL
• Manufacturer code: PL124
• Supplier SKU: AQS19
• Product type: External antiparasitic and antifungal aquarium medication
• Primary treatment: Freshwater white spot
• Other applications: Certain external parasites and fungal conditions
• Active ingredients: Formalin and malachite green
• Contains copper: No
• Standard dosage: 5mL per 20 litres
• Sensitive fish dosage: 5mL per 40 litres where specified
• Coverage per standard dose: Approximately 1,000 litres
• Four-day course coverage: Approximately 250 litres at standard daily dosing
• Suitable for: Compatible freshwater ornamental fish

Frequently Asked Questions

What does Aquasonic Formalin/Malachite Solution treat?

Aquasonic Formalin/Malachite helps treat freshwater white spot disease, susceptible external protozoan parasites and certain fungal infections affecting ornamental fish.

How much Aquasonic Formalin/Malachite should I use?

The standard freshwater dosage is 5mL per 20 litres. Some sensitive species require a reduced dosage of 5mL per 40 litres. Always follow the instructions supplied with the bottle.

How much water does the 250mL bottle treat?

One 250mL bottle treats approximately 1,000 litres in a single standard application. For a four-day treatment course involving daily dosing, it treats approximately 250 litres in total.

Can I use Aquasonic Formalin/Malachite with tetras or loaches?

Some tetras, loaches, juvenile fish and scaleless species are sensitive to this medication. Manufacturer instructions include a reduced dosage for sensitive species. Check compatibility before treatment.

Is Aquasonic Formalin/Malachite safe for aquarium shrimp and snails?

No. This medication should not be used in aquariums containing ornamental shrimp, snails or other sensitive invertebrates.

Does Aquasonic Formalin/Malachite contain copper?

No. The listed active ingredients are formalin and malachite green. However, copper-free does not mean the product is safe for invertebrates or sensitive fish.

Should I remove activated carbon during treatment?

Yes. Activated carbon can remove medication from aquarium water. Remove it during treatment while maintaining biological filtration and strong aeration.

What is the difference between the 100mL and 250mL bottles?

Both sizes contain the same treatment formulation. The 250mL bottle offers more medication for larger aquariums or repeated treatments, while the 100mL size may be more suitable for smaller aquariums.