Treatment of white spots (Ich) in tropical ornamental fish

Treatment of white spot disease (Ich) in fish

Because not all stages of the Ichthyophthirius life cycle are affected by treatments, multiple treatments must be administered to capture individual Ichthyophthirius organisms at vulnerable life cycle stages.

For example, during the first day when a chemical is added to the water to kill Ichthyophthirius, only a certain percentage of Ichthyophthirius organisms will be susceptible to the chemical. Two days later, many of the surviving Ichthyophthirius organisms, which were embedded in the skin of the ornamental fish, will enter the vulnerable stage of their life cycle; chemical treatment on this day will kill these susceptible organisms. To trap all Ichthyophthirius organisms at a treatable stage, three to seven treatments may be needed depending on the water temperature. The effectiveness of the treatment should be evaluated by a fish health professional after the third treatment to decide whether to continue the treatment program. Mortality rates should be observed and fish samples from the infected pond should be examined for Ichthyophthirius under a microscope. Spacing of treatments varies with temperature. Some fish health professionals believe that treatments should be applied every day, even in colder weather, rather than skipping days in between. Ichthyophthirius appears to have a distinct temperature range in which it is infectious. It has been observed that temperature changes of 15 degrees F or more above or below the temperature at which an Ichthyophthirius case is detected will terminate the disease episode, regardless of the number of treatments performed.

In some cases, one or two treatments may be all that is needed to buy aquarium fish time until such a temperature change occurs. The US Food and Drug Administration has approved the use of formalin to control Ich in trout, salmon, catfish, largemouth bass, and bluegill. The FDA has also granted copper sulfate (CuSO4) and potassium permanganate (KMnO4) deferred status, which means that these treatments can be used without legal prosecution, but may lose deferred status if evidence of a hazard to humans is found. the human consumer. Other chemicals should not be used to treat Ichthyophthirius Ich in food fish. Of the three therapies, copper sulfate is the least expensive.

Treatment rates for various chemicals are described below. Adding an extra chemical just in case may kill or stress the fish being treated, while using less than the required therapeutic dose may not be effective in killing the parasites that cause fish death.

Formalin

Formalin is a solution of 37 percent formaldehyde in water with 6 to 15 percent methanol added as a preservative. It should be stored at temperatures above 40 degrees F.

Formalin can be used as a bath treatment for up to one hour at 125 to 250 parts per million (ppm) (4.4 to 8.8 milliliters per 10 gallons; 32.8 to 65.5 milliliters per 10 cubic feet). The treatment rate should not exceed 167 ppm in warm water fish when temperatures exceed 70 degrees F (21 degrees C), or in trout and salmon when temperatures exceed 50 degrees F (10 degrees C). Tanks should be rinsed with clean, aerated water after one hour, or sooner if the fish show signs of stress. Formalin is used as a pond treatment at 15 to 25 ppm. This would be 4.5 to 7.5 gallons of formalin per acre-foot (one acre of water 1 foot deep).

The formalin should be applied evenly throughout the pond. Formalin must be handled with great care because its vapors are dangerous and can damage the mucous lining of the nose and throat.

Copper sulfate (CuSO4)

Copper sulfate (CuSO4), sometimes called bluestone or simply copper, is the cheapest chemical available to treat Ich. Copper sulfate is used as an indefinite treatment (ie, applied to water and allowed to sit without further dilution of treatment). The treatment rate is determined by the total alkalinity concentration of the water being treated; the copper sulfate treatment rate in ppm equals the total alkalinity divided by 100. For example, if the total alkalinity of a pond/aquarium/tank water were 85 ppm, then the copper sulfate treatment rate would be 85/100 = 0.85 ppm. In a pond, the pounds of copper sulfate needed in this example would be:

Acres x average depth in feet x 0.85 ppm CuSO4 x 2.7 lbs CuSO4/acre-ft/ppm = lbs. CuSO4

In a tank measured in gallons, the grams of CuSO4 needed (when total alkalinity is 85 ppm) would be:

Gallons x 0.85 ppm CuSO4 x 0.0038 grams CuSO4/gallon/ppm = g CuSO4

In a tank measured in cubic feet, the grams of CuSO4 needed (when total alkalinity is 85 ppm) would be:

Cubic feet x 0.85 ppm CuSO4 x 0.0283 grams CuSO4/gallon = g CuSO4

Potassium permanganate (KMnO4)

Potassium permanganate (KMnO4) (often referred to as potassium) is an oxidizing agent that oxidizes organic materials in water, including protozoan parasites or external bacteria that live on the surface of fish. It is usually used as an indefinite treatment in ponds at a rate that depends on the amount of organic matter in the water. Two (2) ppm KMnO4 is the minimum dose required to be effective against external parasites such as Ich, while nutrient-rich waters with strong algae blooms need a higher amount of KMnO4 for effective treatment. (One author knows of a case where 20 ppm KMnO4 was needed to reach an effective treatment level.) A potassium permanganate demand test is often used by aquatic biologists and extension specialists to determine the most effective, yet safe, treatment rate.

A traditional technique for deciding the correct dose of KMnO4 is to add 2 ppm at a time until a wine red color is reached in the water, and this color must persist for at least 8 hours to give an effective treatment. The person applying the potassium permanganate must ensure that the chemical is completely dissolved during application so that an accurate assessment of the color of the water can be made. On at least one occasion, the water seemed to not turn red after several applications of 2 ppm KMnO4, then suddenly the water turned a deep red color as the undissolved KMnO4 dissolved all at once, killing everyone. the fish in the pond. However, generally this technique of applying 2 ppm at a time works well. A KMnO4 bath treatment at 10 ppm for 15 to 20 minutes (approximately 1/2 teaspoon level of KMnO4 per 100 gallons of water) is an effective short-term treatment. Water should be readily available to rinse the tank quickly if the fish show signs of stress. The following example shows calculations for the amount of KMnO4 to add to a pond that needs 2 ppm of KMnO4. 1 acre-ft x 2 ppm KMnO4 x 2.7 lbs. KMnO4/acre-foot/ppm = 5.4 lbs. The amount of KMnO4 to use in a 300 gallon tank of water (before adding fish) to achieve a concentration of 10 ppm for a 15-20 minute bath treatment would be calculated as follows: 300 gallons of water x 10 ppm x 0.0038 grams KMnO4 /gallon/ppm = 111/2 grams KMnO4

Salt (sodium chloride; NaCl)

One of the best treatments and preventatives for Ich has been 2 to 3 parts per thousand (ppt) of salt indefinitely. This is generally a very effective treatment for tanks and recirculating systems, but is not cost effective for ponds.

See http://www.tropical-exotics.co.in for information on the different ornamental fish that commonly get this disease in India.