Fulminant Gill Rot
By Galen Hansen M.D.
There is such an aggressive deadly infection hitting many Koi hobbyists and dealers, particularly in California. The disease has been so overwhelming and devastating that many of us feel it is important to alert any and all who have Koi to the experience of those affected. The infection, not yet clearly identified as to pathogenesis, results in nearly total wipeout of all those so unfortunate to acquire it.
Summary of Facts concerning disease
The disease is largely too far involved and irreversible by the time you detect it.
The most common finding is large scale Gill Rot with at least half the gill being necrotic (eaten away).
It is caused by a very contagious organism, either viral or bacterial or both.
No consistently reliable treatment has been identified to date.
Once the epidemic was over it was over.
Condition is very much associated with husbandry factors and is associated with a range of opportunistic bacteria including Pseudomonas spp and myxobacteria.
This condition is characterised by erosion of the fins, tail and snout. The lesions may be subtle, but frequently lead to loss of complete fins and even the tail. Active lesions vary from low-grade ulceration to aggressive necrosis.
Any form of chemotherapy is of limited value and antibiotics should only be used as last resort because the response is often disappointing and antibiotic resistance is likely to be encouraged.
Ideally this condition should be controlled by good husbandry practices and quarantining. The use of immunostimulants is suggested.
Aeromonas Salmonicida, which causes Goldfish Ulcer Disease, was almost certainly introduced into Australia with fancy goldfish from Japan. Apart from goldfish it has caused natural disease in carp and silver perch in Australia.
Typically, affected fish exhibit ulcers of varying size on the body. Depending on the water temperature these may develop rapidly or gradually expand over time. Some fish recover especially with treatment but may have scars as a result
A wide range of antibacterials can be used. Unfortunately antibiotic resistance builds quickly and the efficacy of any particular antibacterial tends to be short-lived.
Fish Immuno Stimulants would have a greater effect, as the prevention is always better than the cure. Immuno Stimulants are now offered by the way of Vaccinations Intravenously and Oral.