Infected fish show signs of asphyxia such as gasping.  They appear weak and lethargic.  Die-offs can reach a mortality rate of over 50% in some cases.  The fish that survive, may be able to re-generate their damaged gill tissue if treated properly.

This disease is seen in the blood vessels of the gill tissue, and it obstructs the circulation of blood through the gills, which makes the gills lose their bright red color.  The gill tissue becomes mottled with patches of brownish discoloration due to hemorrhages mixed with whitish areas of disrupted blood flow, resulting in necrotic tissue.  In some cases, the necrotic areas may slough off and allow the gills to be invaded by a secondary disorder such as a Saproglenia fungus.

Gill infection with Saprolegnia fungus looks almost identical to Branchiomyces.  This suggests that Branchiomycosis may belong to the family "Saprolegniaceae".

Mycotic infections in goldfish and koi are mainly associated with stress or injury.  Infection with Branchiomyces is rapid, and is mainly caused by algal blooms, overcrowding, high water temperatures, and high levels of ammonia in the pond.

Prevention of Branchiomycosis can be accomplished by maintaining good water quality, removing dead fish and preventing the accumulation of decomposing organic matter.  Decreasing feed, and improving water flow to prevent the build up of ammonia are also crucial.  Thinning out fish to prevent crowding and stress should also be practiced.

Treatment and Control:

A long term bath in Acriflavine Neutral or Forma-Green for seven days helps this condition.  If you decide to use the Acriflavine Neutral, you might want to do this in a holding or quarantine tank because it's awfully hard to remove from the water.

Water changes and the reduction of algae with the  use of a nitrifying facultative bacteria like Aqua Gold can prevent Branchiomycosis and many other diseases like Aeromonas (hole in the side disease) from developing in koi ponds.

Remember: Water quality is key, in any environment that contains tropical fish.



Best Regards,

Dr. Gary Aukes; Pharm D, Dr. Brian Aukes; PhD., and the staff of National Fish Pharmaceuticals.

Fish Articles

Items that can be used to treat the diseases listed in this article include:


Acriflavine Neutral

Aqua Gold

 Home ı Articles ı Prevention ı Fish Diseases ı About Us ı Contact Us ı Terms of Use ı Privacy Policy ı Shipping ı Products

©1995-2006 - Site Map - Site Design by Brian Aukes & AFAM LLC.