Koi Diseases & Symptoms

Text-To-Speech Koi Diseases & Symptoms



Argulus (Fish Lice)
Fish Louse. (Argulus) are flattened with a roughly round body with eight legs and two large hooks (not usually seen) to attach to the fish. It is about 1/8th of an inch and the dark eye spots give it away. It sucks blood, so removal involves making/leaving a wound which needs to be treated with a topical antibiotic. Eggs are attached to things in the tank and pond and they hatch out about a month later. They are suspected of spreading other diseases.
Brain Flukes
White fleck in eye, swimming oddly or in circles.
Mottled gills, bluish or grayish irregular streaks hot temps and bluish color are the tip-offs.
Clamped fins, gasping, lethargy, hiding, and thick slime coat.
Nearly always causes little red hemorrhages, especially under the chin, but also along the back.
Dactylogyus aka Gill Flukes
First, dark red at base of pectoral fins. Later symptom, gasping at the surface, gloppy gills, and flared gills.
As the water warms up, and the water quality degrades, epistylis can occur. They are more likely to be found on fins especially the edges.
Gyrodactylus (Flukes)
Flashing, listless, frayed fins, slime coat thick or rough.
It is one of several protozoans that attack the gills. In good water with good aeration, it does not cause high mortality. It looks like a white cyst in the gills.
Pitting, depigmentation along the lateral line near the head, thin white threads trailing.
White specks like grains of salt all over most of the fish check if temperature of water has change suddenly, check water parameters.
Lernea aka Anchor Worm
Only females attach into the muscle of the fish and feed. The long body and forked tail is diagnostic, a microscope is not needed.
Lethargy, flashing, dry patchy looking skin, yellowish tinge, and thick slime coat.
It thrives on the slime coat, so that conditions that stimulate the slime coat, like toxic water actually increase the numbers.

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Bacteria & Viruses

It gets going quite early in spring. Look for any red sore. Blood at the base of the pectoral fins may be the first indication of an internal infection.
White threads blowing in and out of mouth, dry skin, skin color darkens, white fungusy or thready looking sores, peduncle disease, red anal vent, chronic bubble eating check for mouth and anal vent for sores, slime coat, mushy belly, gills light to dark brown patches and white sores.
Lymphocystis aka Carp Pox
If it is greasy, buff colored and shiny, it is most likely carp pox. Especially, Koi usually get Carp Pox if the water is just warming up or is cooling down (in your area).
Skinny Disease (Getting Thin)
Fish are typically thinner in spring after not being fed over winter. If there is a high load of fish in the pond, there might not be enough natural food and the fish must be fed. But the fish seem to be eating but look sucked in at the gill plates, the head looks large compared to the body and the body is “skinny” , this is most likely “skinny disease”.

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Symptoms Behavior

  • Bent spine
  • Blindness
  • Clamped Fins
  • Darting
  • Eating Bubbles
  • Flashing
  • Floating
  • Gasping at surface
  • Head Standing
  • Jumping
  • Lethargy
  • Listing to the Side
  • Spasms
  • Tail Standing
  • Whirling
  • Won’t Eat
  • Yawning

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Symptoms Appearance

  • Black Spots
  • Black Streaks on Fins
  • Body Swollen
  • Bubbles Under the Skin
  • Bulging Eyes
  • Changing Color
  • Dropsy
  • Fin Rot
  • Fin Shredding/Splitting
  • Getting Thin
  • Hole-in-the-Head Disease
  • Loosing scales
  • Lump(s)
  • Protrusions of the Anal Port
  • Red Sores
  • Red Spots
  • Red Streaks
  • Redness at Base of Pectoral Fins
  • Scales Sticking Out (Pine Cone)
  • Sudden Death
  • White Flecks in Eye
  • White Spots
  • White Spots on Gill Covers
  • White Spots on Head Growth

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