Cryptobia iubilans in juvenile Discus

5dd63f31-34f0-4d70-bbbb-80b607dd7fae

Editor's Picks
Features Post
The brightest pupils
04 October 2021
Features Post
Dealing with egg ‘fungus’
04 October 2021
Features Post
Rathbun’s tetra in the wild
13 September 2021
Fishkeeping News Post
Report: 2021 BKKS National Koi Show results
13 September 2021
Features Post
The World's forgotten fishes
16 August 2021


A new veterinary study of Cryptobia iubilans infections in juvenile Discus has just been published in the Journal of the American Veterinary Medicine Association.

Cryptobia is a flagellated protozoan parasite similar to the Hexamita and Spironucleus parasites responsible for hole in the head disease. The disease usually causes granulomas in the stomach, but in severe cases, systemic infections can arise which affect the blood and organs, including the liver, gall bladder, ovary, eyes and brain.

The study, which was undertaken by a team of scientists from the Tropical Aquaculture Laboratory, Department of Fisheries and Aquatic Sciences, Institute of Food and Agricultural Sciences at the University of Florida, used a specialist transmission electron microscopy (TEM) technique to identify the parasites.

The affected Discus, Symphysodon aequifasciata, were purchased from commercial Discus suppliers. The study found that mortality and morbidity rates were directly linked to a number of factors, including secondary diseases, diet, species, size, age and, most important, water quality.

Unlike similar diseases, the often prescribed metronidazole (flagyl), didn't appear effective against C. iubilans. Instead, the study found that a bath of dimetridazole of 80mg/l for 24 hours repeated daily for three days, or 2-amino-5-nitrothiazol at 10mg/l for 24-hours repeated daily for three days, was the most effective treatment.

Importantly, the latter medication is available in the trade without subscription, as it is the active ingredient in JBL Spirohexol.

For more information see: Yanong RP, Curtis E, Russo R, Francis-Floyd R, Klinger R, Berzins I, Kelley K, Poynton SL. (2004) - Cryptobia iubilans infection in juvenile discus. J Am Vet Med Assoc. 2004 May 15;224(10):1644-50, 1606.