Below is a list of articles with the most recent ones listed first.
Anchor worm is more common in coldwater fish, especially newly imported specimens. Infected fish are vulnerable to secondary infections, such as fungus and heavy infestations can cause weight loss and even death.
Before Costia kicks everyone's rear-ends, please read the following.
Chondrococus columnaris and Cytohaga columnaris bacteria can cause greyish white growths, similar to fungus on the head area of fish, the gills and the fins.
Cryptobia is a flagellate which is often mistaken for hexamita as they are very similar in appearance.
Dropsy is not a disease it's a name for a fishes shape. It means generally swollen and scales standing out from the body.
Dystocia (Egg Compaction)
The swelling of the abdominal cavity is a problem that can simulate many other form of disease or bacterial infection.
The objective of most Koi keepers having purchased a beautiful specimen, the quest is to help the Koi to grow to its full potential by providing it with a high protein diet and an expansive pond.
This occurs where water is disturbed or agitated by a venturi or waterfall and the resultant bubbles will drift around the surface until they burst. These bubbles retain their shape because of the stabilising properties of complex dissolved compounds within the water.
Bleeding from the gills is not uncommon in the springtime and is almost always ONLY seen in female fish, after some stress, such as capture, or injection.
Gill disease is down to the fishes condition. we are back to water quality again. As with any infection first think water water water and test test test.
Gill Maggot - Ergasilus
It is only the female that attacks fish, the male stays in the plankton swarm.
Koi Herpes Virus (KHV or CY-HV1)
KHV has now been been reclassified as CY-HV1.
The following is reproduced with permission of CEFAS
There are other diseases which mimic the symptoms of KHV.
There is not a treatment that can be bought over the counter.
Myxozoa, or myxidium serotinum-myxobolus koi.
This parasite infects many types of genera and species
Neon Tetra Disease (pleistophora hyphessobryconis)
Pleistophora hyphessobryconis is a protozoan/parasite disease affecting many tropical fish and goldfish (those in aquariums) Its common name is Neon Tetra Disease.
I've very little to say as there is only one treatment - injections. Nothing else works, but first check to be sure it's not a bruise.
Salt - by Doc Johnson
I recommend that you use salt, before you try anything else for parasites. I recommend salt so often because it has so many benefits over other medicants.
Sepsis mostly only affects one fish in a collection at any one time. This condition is when bacteria -
Swim bladder Problems
Swim bladder problems are not as common in Koi as in fancy goldfish.
Tapeworm in Koi are nearly always bothriocephalus acheilognathi. They can be a problem mainly from planted semi wildlife koi ponds or bought in fish from raising ponds or mud ponds.
A member of the genius Mycobacterium, the Fish TB causing organism Schizoblonta is endemic in both marine and freshwater fish, (and can be caught by amphibians, reptiles and humans)
Ucers are external bacterial infections, bacterial erosions and bacterial sepsis of Koi carp. There no such disease as ulcer disease.
A Koi keeper has 3 main problems apart from KHV:
3. White Spot. and this one is linked to the previous two.
Freshwater Ich - Ichthyophthirius multifilis - is a killer of very small fish, and can cause "redskin" disease in the winter regardless of fish size.