Ten Things to Check If Your Koi Seem Sick

In This Chapter

• External forces: It’s all in the water (values and temps)
• Physical symptoms: From chin to fin
• Finny behaviors: Swimming and socializing

Koi don’t just turn over and die. They show signs — some overt, some not — that something’s funky. Keep a close eye on your pond and watch for any of the signs we talk about in this chapter; then take action before you finny friends get really sick. (Try not to be paranoid, though, or you’ll defeat the purpose for keeping koi — to sit back, relax, and enjoy them.) Chapter Spotting and Treating Common Koi Ailments has all the important details on diagnosing and treating a sick fish, but this chapter guides you through the checkpoints for reaching a diagnosis.

The Pond’s Water Quality

You’ll hear this advice so much that you’ll begin muttering it in your sleep: The health of your koi is directly related to the quality of their pond water. When water chemistry values get out of whack, especially the ammonia and nitrite levels, they compromise your koi’s immune systems. Practically any nearby bacteria or virus can move in and set up housekeeping. Then you and your koi have compounded problems. Head back to Chapter Maintaining Your Pond to find out how to check and fix the water quality if a chemical’s out of balance.

The Pond’s Water Temperature

Is the pond’s water temperature between 75 and 85 degrees F? It should be. Koi are remarkably adaptive fish, but they have a limit to what they can deal with successfully. If the water’s too cold, their immune systems can’t fight off infection, particularly the opportunistic cool-water bacteria, Aeromonas and Pseudomonas (see Chapter Spotting and Treating Common Koi Ailments). When water temps near the mid-80s and the normal afternoon pH rise elevates the ammonia level, your koi are subjected to the flesh-curdling effects (fin rot and gill plate swelling) of ammonia. Think of Goldilocks’s porridge when it comes to pond temps — not too hot and not too cool. For the how-to on correcting the pond’s water temperature, consult Chapter Maintaining Your Pond.

Your Koi’s Scales

Do any of the scales stick out from the body? Those that stand out are called pine cone scales, and they indicate a severe internal infection, the kind that makes the body swell up. This isn’t a good sign at all, and it calls for all of the following steps:

• Immediate transfer to a spacious quarantine tub (spacious because your koi’s going to be there for a while)
• Antibiotic feed or injections
• Careful monitoring

Don’t be surprised if this symptom also calls for a one-way trip to the garbage can. After a koi undergoes this sort of internal pressure, recovery is a surprise.

Your Koi’s Gills

Does the fish seem to have trouble breathing? Gill plates swell and can’t accept enough oxygen when the water’s ammonia levels are too high. Your poor koi not only feels awful, he’s also oxygen-deprived. Make an immediate 30 percent partial water change and track down the cause of the ammonia problem. Check the color of the gills — are they the color of your own gums? (Good.) Are they pale pink? (Not good.) Do they look spongy, like moist bread? (Oh, not good.) Gill plates that develop white patches and appear to be disintegrating may indicate koi herpes virus. This virus is highly contagious and is usually fatal. See Chapter Spotting and Treating Common Koi Ailments for more details.

Your Koi’s Finny-Fin-Fins

Human eyes may be the window to the soul, but the window to your koi’s health is through the thin skin covering their fins:

- Tattered fins mean the koi has fin rot or has been handled and netted too much.

- Bleeding fins indicate rough handling, poor water quality, or a pond bottom that’s too rough.

- Swollen spots on the leading edge of a fin may indicate carp pox. (You can’t do anything about this virus except increase the water temperature enough to activate the koi’s own immune system. Increase water temps only a few degrees a day to enable the koi to adjust.)

Check out Chapter Spotting and Treating Common Koi Ailments for additional fin remedies.

Your Koi’s Underside

As part of a general checkup, bowl your koi and lift it to check its underside, or bag it and examine its underside through the bag. Aeromonas, the cause of hole-in-side disease (see Chapter Spotting and Treating Common Koi Ailments), tends to erupt as an ulcer on the underside of koi, particularly between the pectoral fins. However, the ulcers can show up nearly anywhere. Aeromonas can also bloat the body and cause pine cone disease.

You can usually avoid the problem by keeping the pond temp above 68 degrees. Treatment consists of bringing the koi inside for a month or two of careful water temperature regulation and antibiotic treatment. Alternatively, you can treat the entire pond with salt, potassium permanganate, or a commercially available antibacterial, or you can admit you don’t know what’s happenin’, baby, and call in a koi vet or a more experienced koi-keeper.

Your Koi’s Body

Does the koi’s body have tiny white spots? This may be Ich (a parasitic disease) or a fungus. Take a scraping and examine it under the microscope to make a diagnosis. (Chapter Spotting and Treating Common Koi Ailments walks you through this process.)

Pet stores carry several off-the-shelf medications for Ich, or you can use malachite green, salt, or temperature manipulation, as we describe in Chapter Spotting and Treating Common Koi Ailments.

The diagnosis of fungus calls for a different approach because fungus is a secondary infection, one that appears after your koi’s protective mucous coating has been damaged. Identify and eliminate the problem (from netting, poor water quality, or inadequate diet) and then treat for the fungus (see Chapter Spotting and Treating Common Koi Ailments for treatment plans).

Your Koi’s Belly-Side Behavior (Are You Being Flashed?)

Do your koi seem to be rubbing their bodies against the sides or bottom of the pond, or are they turning over at the surface of the water? This maneuver is called flashing, and it usually indicates a parasitic infestation or an electrical short in the pond.

External parasites on your fish are about as comfortable as head-to-toe poison ivy on you. Do a skin scrape to ID, and then treat for the little varmints.

In case of a possible electrical problem (damaged electrical cord, cracked housing, or the suspicious scent of bad circuitry), unplug, remove, and examine any submerged pumps or filters for a possible short circuit.

 Your Koi’s Swimming Style

Do your koi swim strong and in a straight line? Koi that have difficulty remaining upright while swimming may

• Have metabolic bone disease
• Have been shocked by an electrical current
• Be in the close-to-terminal stages of disease
• Have been exposed to toxic substances such as fertilizer or insecticides

These are all bad news. No matter what the exact cause, you need to identify it and deal with it (but turn off the power to your pond before you try to pull up that submerged pump, please!). Chapter Spotting and Treating Common Koi Ailments can help you with these problems.

Your Koi’s Social Savvy

Does a formerly friendly koi seem to avoid contact with other koi and with (gasp!) you? Sick koi often stay away from other koi and may be uninterested in food. A koi that suddenly elects to avoid other koi is the proverbial canary in a coal mine, at least in terms of his health. Keep an eye on him for a couple of days. If he doesn’t elect to rejoin the herd, you may want to bowl him to look him over. (Let Chapter Spotting and Treating Common Koi Ailments be your guide for your observations.)

by R.D.Bartlett and Patricia Bartlett