​​Case Consult: Gill Disease

"....I wondered if you can look at these photos of a male Goshiki I found sitting on the bottom of my koi pond today. In 7 years we have never had a gill issue so this is very strange for us.  Do you have any ideas of what this can be?  I am very concerned it is contagious.  I have isolated the fish into quarantine. 

Warm Regards,

John "

Dr Johnson:


So, that looks like any of a number of things, but bacterial gill disease comes to mind. 
You should DEFINITELY look at the gills of some other fish. Not doing so was a mistake I made in a former life. And I had a widespread problem and did not know it til fish started dropping but HARD., 

Parasites commonly set that up. 
Too infrequent water changes, often do too. IN particular in warm water of summer. 
In summer, the immune system of Koi is at it's best. But that's no match for warm water, low dissolved oxygen and high levels of background pollution which correlate nicely with a measurable parameter, which is NitrAte. Check that. 

If you want to, you can empirically treat parasites, OR check them. 
If you know how to use a microscope or know someone who does, you're in luck. 

Primary bacterial gill disease seldom happens but a significant dip in Dissolved oxygen was used in one study b Elmore et al to induce bacterial gill disease in fish intended for study and caused it Every. singe. Time. The theory I have on that is that the gill tissue starts dying like oxygen deprived brain tissue and even when re-perfused is vulnerable to infection. 

If you want to Shotgun the treatment of the fish consider a major water change to cool the system and shotgun some Proform C or better still, Mardel Clout. Clout does not sag dissolved oxygen like Formalin does. It doesn't burn gills. It's gentle on filter bacteria. But it's kind of expensive in systems over 2-3000 gallons. 

If you wanna read about shotgunning Mardel Clout, follow this link

If you wanna buy Clout, use this link and they give me fifty cents. 

If you are going to buy Pro Form C formalin / malachite mix, use this link and they'll kick me back fifty cents. 

People with mental illness often fully believe that they're the normal ones, and that it's everyone else's fault that their lives seem to be nonstop turmoil, persecution and drama. They also fail to acknowledge the incalculable damage their psychotic nearsightedness does to the ones around them. I know because I was married to such a person for four years and watched as her parents' and childrens' lives were destroyed or damaged forever. Thanks e-Harmony.