It is absolutely true that Koi Disease is often the result of a parasite invasion, but almost always; the parasites require some sort of stressor to make the fish vulnerable. Notable exceptions exist, but if you are aware of water quality management, and can identify disease factors in your livestock, you can prevent more diseases and save fish lives.
Some of the Below content is borrowed with permission from Dr. Erik Johnson's lecture notes and book
Koi Health & Disease
 

PARASITES
Divided into three broad classes: Protozoans, Trematodes, and Crustaceans
PROTOZOANS
Ich, Trichodina, Chilodinella, Costia, Epistylis

ICH

· Ich causes white spot disease and can account for mortality in smaller Koi, especially when crowded or chilled. · Ich is controlled by Salt, described later.

Trichodina
· Trichodina (cousin: Tripartiella) causes flashing and spiderweb lesions in the skin. Can precipitate Ulcer Disease. · Trichodina responds readily to salting, unless it is the Japanese import variety. Double dose salting (0.6%) does fine for these.

Chilodonella
· Chilodonella causes respiratory damage and excess mucus production. Salt is the treatment of choice, clearing losses within 24 hours. · Chilodonella is one of the fastest killers of fish, even large ones under the right conditions of crowding and chilling. *Fish gather at the water fall - sudden death

Costia
· Costia (Ichthyobodo necatrix) causes much the same condition as Chilodonella, and is also a rapid killer of fish, who die after suffering severe gill damage. *Fish gather at the water fall - sudden death · Salt is the treatment of choice, clearing losses within 24 hours. Rare salt resistant forms exist.

Epistylis
· Epistylis looks like a goblet under the scope, but looks just like Fungus to the naked eye. Not a fish killer. This belies a dirty-pond or filter, shame shame! · Salt is the treatment of choice, clearing Epistylis within 24 hours.

Flukes:
· Flukes: Gyrodactylus/Dactylogyrus are larger parasites, easily diagnosed from skin and gill scrapes under the microscope. ·,Clearance by SUPAVERMor PRAZI is ideal.
Potassium permanganate is also excellent · Actively writhing "worms" with hooks on one-end and suction cups on the other.
· Flukes cause FLASHING! Spiderweb lesions in the skin and reddened fins. Gill damage may be severe, and Flukes kill lots of fry annually. · Also, Flukes are the NUMBER ONE cause of Koi Ulcer Disease. They carry pathogenic bacteria on their haptens and inject the bacteria into the sores they create.
· Look for these anytime SALT fails to limit your losses or sickness · Scan under 40X combined power with iris diaphragm closed and light low.

Lernea - Anchor worm

· Lernea - Anchor worm appears as a tiny tan or greenish worm sticking out from the lips, fins or scales of fish. Causes a red sore at the spot they are attached, sometimes the red spot is all you can see from a distance. · Highly contagious, these can come in with water or fish. They have a freeswimming larval stage. Dimilin™ is the treatment of choice for both Lernea and Argulus..

Argulus - Fish Lice
· Argulus - Fish Lice look like little (4mm) greenish or yellow "flying saucers" and are easily visible with the naked eye. They suck blood with a tiny stiletto and are very damaging to fish.

Ammonia
· Causes redness of fins, general poor health, excess mucus production, flashing, and pinecone disease. · Usually tested with Nessler's Drop Type tests - Salicylate tests more accurate, both can be negated by de-chlorinator.
· Made from rotting fish wastes/urine/food · Directly irritating to fish gills and tissues
· More toxic at pH above 8.0 · Ammonia is removed from the environment by beneficial bacteria called Nitrosomonas
· After (the regrettable) addition of aldehydes such as Formalin or Ammonia-binder agents, you must test with Salicylate reagent tests.
· You can control Ammonia with partial water changes, Ammo-Lock 2, Lymnozyme’s KiFi bacteria, BRF13A or the addition of Zeolites.
· I generally discourage the use of chemicals for Ammonia binding. Water changes are preferable. · Wet dry filtration and Bead filtration are superior modes of filtration.

Nitrites
· Ammonia is converted into Nitrite by Nitrosomonas Nitrite is converted into Nitrate by Nitrobacter · Nitrites cause reddening of the fins and irritation of the gills, gasping + excess mucus.
· Nitrites bind the fish Red Blood Cells resulting in suffocation and "Brown Blood Disease". · Nitrite toxicity is temporarily reduced by the addition of salt at one teaspoon per gallon of water.
· Nitrites can be "reverse" created from Nitrate under anaerobic conditions. (Deep sand, glutted filters, stalled sand filters etc.) · Nitrites should be controlled with wet-dry filtration and water changes as needed.
· Nitrite toxicity is only weakly reversed by addition of Methylene Blue.

pH
· Simple drop type test with Bromthymol Blue · Stay above pH 7.0 for best results with Koi
· pH can "crash" to 5.5 overnight due to fish, plant and bacterial activity without adequate buffering of water - fatalities result · Baking Soda (Check Total Alkalinity before its use, though. (Use one teaspoon per ten gallons if the TA <100),
· pH Pill (www.koivet.com/phpill.htm) Bone meal, or Seachem Neutral Regulator or any of many commercial buffers are recommended. · Low pH affects appetite, but later can cause illness and death. If crashed, raise it at once!

NITRATE
· Made from Nitrite by Nitrobacter · Toxic above 120 ppm :
· Signs include red streaking in fins, dilated blood vessels in fins and skin, “heavy smelling water”, and lethargic fish. · Remove by starting some live planting, or water changes. Allow algae to grow on the liner!
· If you use Simazine or another Algae destroyer, you will have no plant Nitrate utilization. This can be hazardous. · Generally non toxic unless plants and algae are specifically excluded. · Nitrates are IMMUNE SUPPRESSIVE!!!
Hydrogen Sulfide H2S
· Produced in anaerobic areas, deep mulm or sand. Under pots and in crevices of liners. · Losses may continue for up to two weeks after correction.
· Treatment is by removal of fish, clearance of mulm and sand, replacement of 100% of the water. Remove fish first! · Signs are respiratory, gasping. Fish hang at surface, lolling for air, and dart madly when disturbed.

Close Window