Acriflavine in Aquariums: Antiseptic Treatment for Wounds and Parasites
Before modern fish medications lined the shelves of every local fish shop, experienced hobbyists relied on a bright yellow-green dye called acriflavine. This acriflavine aquarium treatment guide from Gensou Aquascaping at 5 Everton Park, Singapore, covers proper dosing, suitable conditions, and important limitations. Despite being an older remedy, acriflavine remains effective against a specific range of problems — and it is still widely available at shops across the Serangoon North area and online on Shopee.
What Is Acriflavine?
Acriflavine is an acridine dye with antiseptic and mild antiprotozoal properties. It was originally developed for human wound care in the early 1900s and later adopted by the aquarium hobby. The compound works by disrupting the cell membranes of bacteria and certain protozoa, making it useful against external infections. It comes as a liquid concentrate, typically in a yellowish-green solution, and turns your tank water a distinctive golden hue during treatment.
When to Use Acriflavine
It works best against external bacterial infections, mild fungal infections on eggs and wounds, and some ectoparasites like Costia and Chilodonella. Open wounds from fighting, fin tears, or abrasions from rough hardscape respond well. Breeders often use it to protect egg batches from fungal attack — a light dose in the breeding tank prevents the cottony white growth that destroys unhatched eggs. Acriflavine is not effective against internal parasites, advanced columnaris, or Ichthyophthirius (white spot disease).
Proper Dosing Guidelines
The standard dose is 1 ml of commercial acriflavine solution per 4 litres of aquarium water for a short bath lasting 30 minutes, or 1 ml per 20 litres for a prolonged tank treatment lasting 3-5 days. Always check the concentration on your specific product — formulations vary between brands. Dissolve the dose in a cup of tank water first, then pour it slowly near the filter outlet for even distribution. Repeat the dose after each water change if continuing treatment.
Precautions and Side Effects
Acriflavine can damage beneficial bacteria in your biological filter, especially at higher concentrations. Running a hospital tank for treatment is always preferable to dosing your display tank. The dye stains silicone sealant, ornaments, and even your hands — wear gloves when handling it. It is also phytotoxic, meaning it will harm or kill aquarium plants. Remove sensitive species like Rotala and Ludwigia before treatment, or medicate in a separate container. Scaleless fish and shrimp are more sensitive, so halve the dose if these inhabitants must remain exposed.
Combining With Other Treatments
Avoid mixing acriflavine with malachite green, methylene blue, or copper-based medications — combining dyes can cause unpredictable toxicity. You can, however, use acriflavine alongside aquarium salt at 1-2 grams per litre for a synergistic effect against external bacteria. If you need to switch to a different medication, perform a 50% water change and run activated carbon in your filter for 24 hours to remove residual acriflavine first. Patience during this transition prevents stacking chemical stress on already weakened fish.
Treating Eggs With Acriflavine
For egg protection, use a lighter dose of 1 ml per 40 litres. This provides enough antifungal action without harming developing embryos. Many killifish and corydoras breeders in Singapore swear by this method. Place the eggs in a small container with gentle aeration and treated water, maintaining temperature at 26-28 °C. Change 50% of the water daily with freshly dosed water until the eggs hatch. Fertile eggs stay clear while infertile ones turn white regardless of treatment — remove the white ones promptly.
Availability and Cost in Singapore
A 100 ml bottle of acriflavine solution typically costs $5-8 at local fish shops, making it one of the cheapest medications available. Online prices on Shopee and Lazada are similar once you factor in shipping. At the standard prolonged-treatment dose, a single bottle treats roughly 2,000 litres of water — enough for dozens of treatments in a typical home aquarium. Store the bottle away from direct sunlight to preserve potency.
Knowing When Acriflavine Is Not Enough
If symptoms worsen after 3-5 days of treatment or if the infection appears to be internal (bloating, loss of appetite, sunken belly), acriflavine alone will not resolve the issue. Stronger antibiotics like kanamycin or a broad-spectrum product may be needed. For persistent problems, getting a proper diagnosis is essential. With over 20 years of experience, Gensou Aquascaping can help you determine whether acriflavine aquarium treatment is the right choice or if an alternative approach is warranted.
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