Using Chloroquine to Treat Cryptocaryon in Fish

Chloroquine, or Chloroquine Phosphate, is an antiprotozoal drug used by marine and aquarium hobbyists to treat fish suffering from Cryptocaryon. The medication is also an effective treatment for Marine Velvet.

What Is Cryptocaryon?Using Chloroquine to Treat Cryptocaryon in Fish

Cryptocaryon is a ciliated protozoan parasite of fresh water fish. This disease is also known as White Spot, Crypto and Ich (Ichthyophthirius multifiliis). It’s one of the most common infections among fish kept in aquariums, and it is predominantly the effect of poorly kept tank conditions.

While Cryptocaryon does occur in nature, it is much more rampant in aquarium environments. If left untreated, the condition can spread quickly and be fatal to the entire fish population in the aquarium.

Symptoms of Cryptocaryon

The most common symptom of Cryptocaryon is white cysts on the skin, gills, fins, or eyes. These cysts are irritating to the fish, so it may exhibit behavior like trying to rub itself along rocks or other items in the aquarium. If the cysts build up on the gills, the fish will have difficulty breathing, forcing it to remain near the surface of the water in order to breathe.

Treating Cryptocaryon With Chloroquine

Chloroquine is an effective treatment for Cryptocaryon, as it is non-toxic to fish and the natural bacteria of the aquarium, but highly toxic to algae and some invertebrates. It is shown to be most effective when used in conjunction with hyposalinity, or reduced salinity of the water.

The typical treatment involves adding five to ten milligrams of Chloroquine per liter of water every five days for a minimum of four treatments. However, your veterinarian or aquarium specialist will provide more detailed instructions for treating your unique case.

Chloroquine Considerations

When using Chloroquine to treat fish afflicted with Cryptocaryon, the sick fish should be removed from the aquarium and placed in a quarantine tank. The water’s salinity level should be maintained under 14ppt, and the tank light should be left off during treatment.

How to Obtain Chloroquine

Chloroquine is only available with a prescription from a veterinarian. While this medication is safe and non-toxic to fish when administered at therapeutic levels, it can negatively affect the health of the fish if it is administered in higher than recommended doses.


Author: Giano Panzarella

[Photo via: Flickr]