R. D. Bartlett

Article / Updated 03-26-2016

Seeking a koi in top-notch health should be foremost in your mind, even ahead of color and pattern. This requirement becomes especially important if the fish must be shipped by air or ride in a vehicle for several hours to get it home. Such handling, even at its best, can quickly stress out a healthy koi for several days. If the fish is below par to begin with, the trip can be fatal. Of course, even generic koi should be free of malformations. Examining koi in a group Before you pick out a particular koi from a group in a quarantine tub or a dealer's show tank, look at them as a whole. Consider the following characteristics about the group: Are they oriented vertically in the water? Fish that are ill may list (tilt) from front to back or side to side. Unless they're feeding, the head shouldn't be oriented toward the bottom of the tank. Do they seem to move easily through the water with no jerkiness? Skeletal malformations, swim bladder problems, and a host of other conditions can disrupt normal swimming patterns. Are the fish rubbing themselves on the bottom of the tank or against objects within the tank? If so, they may be trying to dislodge parasites. Are the koi swimming about in a frenzied fashion, or do they seem unusually listless? Both behaviors can indicate water quality problems or disease. Are the koi gasping or gulping air at the surface of the water? This behavior can indicate low oxygen levels (which eventually stress the fish) or water quality problems. If the answers to the preceding questions raise any concerns, ask to see another batch. Better yet, resist your impulsive urge and find another source. However, if the koi pass the group test with flying colors, you're ready to take a closer look. Assessing a single koi Select the fish that interests you the most and ask to have it placed in a bowl. Take a few minutes to study it close up. Before you fall in love with its color or its pattern, get steely-eyed about its health. Expensive or not, buying an unhealthy fish makes no sense. As you give the koi a good inspection, ask yourself the following questions. If you answer "Yes" to any of them, move on to another fish, tank, or supplier. Does the fish have any rough spots? Do its scales seem to puff out away from the body? Koi whose scales stand out from their body like a bas-relief may be exhibiting pinecone scale, a symptom of an overall internal infection, or enteritis, which causes such pressure from within that the fish actually bloats, pushing the scales out. This symptom is a very bad sign. Is it missing part of a fin or part of its tail? Looking at the overall proportions of the fish, do you notice any stubby parts? Is its mouth asymmetrical or its snout sharply pointed? As the fish swims past you, is one side of the body wider or more curved than the other, rendering the fish asymmetrical in appearance? Does the tail curve up or wiggle to one side only? Are the eyes cloudy or protrude abnormally? You can also ask the dealer to bag the fish. When it's in the bag, you can examine the koi's mouth, underside, and tail. Signs of infection, such as fuzzy, grayish, or white patches, may appear on the lower aspects of the koi and aren't otherwise easy to see. Fish that look healthy may still carry external parasite eggs that won't hatch until conditions are right. Be aware that transferring the fish to a new pond may give these eggs the opening they need to proliferate, particularly if the fish has been in a cool pond and is moved to your warmer pond. This problem doesn't mean you bought an unhealthy fish or that the vendor's a crook. No treatment kills external parasite eggs.

Article / Updated 03-26-2016

Cotton wool or cotton ball disease is a charming name for Saprolegnia — a nasty fungus that grows when bad water quality stresses your koi. Expect to find it when the water contains quantities of uneaten food and when the pond has too many koi for its size. Fungus can attack any weakened portion of a koi, from the skin to the gills. It usually takes hold opportunistically, when the koi are stressed. Be sure that you always check for the presence of fungus when your fish suffer an unrelated trauma or illness. When a koi has cotton wool fungus, the fish develops what looks like a fine-textured fur coat over its body that's actually mold growing on the skin. Sometimes the fungus looks like a pale-orange or ivory-colored layer. As the disease progresses, the fungus grows longer, cotton-like tufts. Treat this disease by correcting the conditions that lead to the outbreak: Decrease the number of koi in the pond. Improve water quality via partial water changes; an upgraded filtration system; an ammonia remover like AmQuel Plus or Zeolite; and increased aeration. You can also use medication against the fungus. Adding methylene blue (a dye commonly used as a fish medication and available at most pet stores) to the pond at a rate of 1 teaspoon per 700 gallons helps kill the fungus, but individually treating each affected koi in a quarantine tub stops the progression of the disease much faster. Either sedate the koi or hold it so you can remove the patches of fungus with a cotton swab. Then dab the affected spots first with malachite green (a fungicide) and then with propolis (an antibiotic and topical treatment). Return the fish to the quarantine tub and watch closely to make certain no secondary fungal or bacterial infection sets in.

Article / Updated 03-26-2016

When you're confident that your new koi are healthy after a three-week quarantine, you can finally introduce them to their aquatic castle, whether it's an aquarium or pond. Koi can go directly from quarantine tub to pond if the pH values and temperatures are close (0.2 range for pH, and a 5 degree Fahrenheit difference for temperature). If you're using an outside pond, keep in mind that the water must be 70 degrees F or higher. Adding a new fish to a too-cold pond shuts down the fish's immune system exactly when he needs it the most. If the water isn't warm enough, leave your koi in its quarantine tub until warmer weather arrives. The pond temperature is likely to be different from your quarantine tub's temperature. Take a few precautions to avoid stressing your fish: 1. Turn off the heater in the quarantine tub and let the tub reach room temperature overnight. You want less than a 10-degree difference between pond and tub temperatures so your fish aren't shocked. 2. The next morning, if the tub and pond temperatures are more than 5 degrees apart, you need to bag and float your koi in the pond. • Use your koi net to bowl your koi (take the handle extension off your net if you're inside). • Pour the bowl into a waiting and partially submerged poly bag or lift your koi into the bag. You want just enough water in the bag to cover the fish so the bag isn't too heavy. Rubber-band the bag closed and lift the bag out of the tub. 3. Carry the bag to your aquarium or pond, ease it into the water, and let it float for 20 minutes to equalize the temperatures. Keep an eye on the bag(s). Don't let them heat up in the sun. 4. Open the bag, lift out your koi, and release it.