Aquarium Fish Acriflavine

angelfish in an aquarium

The orange pigment dye acriflavine, also known as euflavine, gonacrine, neutroflavine, and trypaflavine, is both an antiseptic and a protozoacide, which means it destroys illnesses caused by parasite protozoans overgrowth (single-celled organisms).

History of Use 

A byproduct of coal tar, acriflavine was initially used as an antiseptic during WWI to battle parasites that caused sleeping sickness. It was also used to treat gonorrhea, although more specialized antibiotics have subsequently replaced it.

Acriflavine is still available as an orange-brown powder and is now used primarily as a topical antiseptic that is often mixed with its derivative proflavine in commercial preparations.

Disease Prevention and Treatment

Acriflavine is used to cure a number of maladies in the aquarium hobby, from bacterial and fungal infections to cleaning open wounds in fish. Acriflavine is also used to disinfect fish eggs, which helps to avoid fungal infection. It can also be used as a substitute for in the treatment of illness in scale-less fish like catfish, elephant-nose, and some Characin species.

Acriflavine should not be used on shrimp, crabs, crustaceans, or other invertebrates. Also, because acriflavine is toxic to living plants, it is not suggested for use in live planted tanks; live plants should be removed before treatment begins. Acriflavine therapy can be done in a separate hospital tank instead.

Following are some aquarium diseases successfully treated by acriflavine:

  • Oödinium pilularis: a protozoan parasite that causes an infection called Velvet Disease
  • : a bacteria that causes an infection known as Columnaris or Cottonmouth
  • : several species of bacteria causing fins and tails to become ragged and frayed; in some cases almost completely eroded
  • Egg Fungus: a mild disinfectant for fish eggs
  • Saprolegnia spp.: a fungal infection of freshwater fish
  • Open Body Sores: bacterial infections causing open red sores on the body

Acriflavine can be put to aquarium water to treat the entire tank or used as a short-term bucket dip for fish. When used as a bath treatment, however, exercise cautious since it may discolor artificial plants and other tank decorations. Remove those objects before applying the remedy to avoid discoloration.

Tank Preparation

Any carbon in the filter will eliminate all acriflavine from the water, thus it must be removed prior to using acriflavine. Acriflavine's efficiency is also inhibited by an acidic pH (below 7.0).

API Stress Coat, Kordon Novaqua, Kordon Amquel, Jungle Start Right, SeaChem Prime, and other Redox Reducing water products should not be used with acriflavine. Before applying acriflavine in the aquarium, wait at least thirty minutes after using the product.

The effectiveness of acriflavine is unaffected by ammonia neutralizing or phosphate absorbing products. It can also be used with antibiotics and methylene blue.

Products Containing Acriflavine

API Fungus Cure is a powder that heals fungus (Saprolegnia spp. & Achlya spp. ), mouth fungus (Cotton Mouth Disease), and Fin and Tail Rot infections in freshwater aquariums. It also aids in the prevention of fungal formation on fish eggs prior to hatching. This drug may create a small discoloration in the tank water, which may be eliminated later with activated carbon.

FishVet Acriflavine-MS is an efficient prophylactic and therapy for oodinium (velvet illness) as well as several external protozoan and bacterial diseases in both marine and freshwater aquariums. Acriflavine-MS is also used to heal open wounds and prevent bacterial egg infections.


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