The water in the transport bag or tank can be chemically treated by the use of additives to help achieve optimal water quality. Different additives are formulated to accomplish various results. Bag Additives should be added to the water before the Koi is placed into the bag.
Bag additives can turn out to be more harmful than helpful. One thing is certain – the water chemistry in a transport bag or tank is constantly changing. It is important to examine the goal of each of the additives as it pertains to transporting Koi.
Oxygen, while the most important item added to the bag, is not counted as an additive. It is important to remember that if the Koi are agitated and stressed during shipment, they will breathe faster and use up the available oxygen in the water more quickly. Excessive movement will dislodge slime coat which will coat the Koi’s gills and limit oxygen uptake.
Detoxification of Ammonia
Koi are constantly producing ammonia, even at rest, and even when fasted.
“It is important to know that 75% of the ammonia secreted by the fish originates from the gills, and only 25% from urine and excrements. This implies that fish constantly secrete ammonium, even when they are not fed. This ammonia builds up to toxic levels quickly in the confines of a transport bag. As stated before, ammonia is less toxic at lower pH and in cooler water. Any additive that raises pH will actually increase ammonia toxicity. Any additive that detoxifies Chloramines, without also binding the released Ammonia, may increase the toxicity of the bag water.
Ammonia toxicity depends on other factors as well, including the health of the Koi’s gills, their respiration rate, the temperature of the water and the salinity of the water. If the Koi’s gills are compromised before shipping, ammonia in the transport bag will continue to damage the gills, and it will take less ammonia to do more damage. Ammonia causes burning to the secondary lamellae where oxygen is transferred.
Detoxification of Chlorine and Chloramines
Either Chloramines or Chlorine is used by municipal water supplies to disinfect drinking water, making it safe for human consumption. Only water safe for Koi should be used in transport, and thus it is assumed that municipal water containing chlorine or chloramines must be treated. If Chlorine alone needs to be neutralized, then Sodium Thiosulfate can be used. Any time Sodium Thiosulfate is used, the water should be tested for residual Chlorine by means of a Chlorine test kit after all the Sodium Thiosulfate has dissolved and the water has been circulated. If Chloramines are used by the water supply and if that water is treated as if it contained only Chlorine, one chemical bond will be broken when the Chlorine component is detoxified, but the Chloramines will then release ammonia into the water. Additional binder may be required, as compared to source water with only chlorine or ammonia. Water treated for Chloramines should be tested for both residual Chlorine and Ammonia. This testing can be done as soon as the binder is mixed into the water, because the chemical bonds form on contact. An additive that detoxifies chlorine and ammonia at the same time would also bind ammonia produced by the Koi during transport.
Slime Coat Enhancement
The need to protect the slime coat when handling Koi has been discussed earlier. Even calm Koi that do not move much in the bag will lose some slime coat due to general banging around during transport. Koi that are stressed from poor water quality tend to be more agitated in the bag, and may lose more of their slime coat. Smaller Koi shipped together will bang against each other in the bag and lose slime coat. The slime coat released into the water degrades water quality by increasing organics and additionally stresses the Koi by clogging their gills, thus making it more difficult for them to extract oxygen from the water. Any slime-coat enhancer that works by irritating the Koi to produce more slime coat causes additional stress by coating the gills and making it even more difficult for the Koi to breath. Any pathogens in the transport water have free entry to attack the Koi in any area in which the slime coat is missing, and in warm water, harmful organisms may reproduce fast enough to damage the Koi even during relatively short transports. Many antibiotics, sedatives and disinfectants have the derogatory effect of reducing slime coat, and damaging gill function. If a Koi’s slime coat is comprehensive and at healthy levels, it will help protect the Koi from pathogens.
Treatment of Osmotic Stress
As mentioned, Koi expend considerable energy keeping water out of their systems. The process of maintaining the water-to-salt balance in Koi is called osmoregulation. Even at rest, Koi must excrete excess water that enters primarily through their gills, and work at retaining salt to maintain osmotic balance. Excess water in their bodies may overload their kidneys and cause death. Koi experiencing osmoregulation problems may appear to be bloated or even look like pinecones, with their scales sticking out, away from their bodies. While there may be many causes for osmoregulatory distress and failure, a simple way to reduce osmotic stress is to add salt (sodium chloride) to the water up to 0.3 %. This reduces the gradient that the Koi’s body must fight to excrete water. The addition of salt to the water decreases the amount of effort that is required to resist the uptake of excess water and maintain salt, thus increasing the amount of energy that the Koi has available to repair damage caused by stress. Other electrolytes including Calcium may also be used.
Detoxification of Heavy Metals
Heavy metals often found in well water include copper, lead, zinc, chromium and mercury. While most municipal water is treated for heavy metals, copper or lead can find its way back into transport water if they are used in the plumbing. As long as water flows through the pipes regularly, the lead or copper does not build up in the water. If a pipe has not been used for a long time, copper may have leached into the adjacent water, and may reach toxic levels if that water is used to transport Koi. Always run water to waste for 10 minutes before filling transport bags or tanks. Heavy metals may be more toxic in a transport bag or tank because the severity of their detrimental effect depends on the ever changing water quality.
Disinfecting the Water
Antibiotics such as bactericides, fungicides, and other disinfectants are sometimes used as bag additives to decrease the bacterial and fungal count in the bag. Many disinfectants that are effective enough to reduce parasites or bacteria are toxic to Koi, especially in the every changing chemistry of the shipping bag, or over a prolonged shipment period. Some substances interact with each other, and either nullify the good effects of each or become toxic in combination. The changing water pH can cause substances to become more or less effective or lose effect entirely, while others precipitate out of solution.
Antibiotics used as bag additives have their own problems. There are no real safe antibiotics; all antibiotics can kill if used inappropriately. Antibiotics are targeted killers. Using a single antibiotic may have no effect, as it may not be effective against the existing strain of bacteria.
Buffering the Water
Buffering is sometimes added to the water to keep the water stable while Koi are being transported. Changing water parameters are often linked to stress in Koi. The most common buffering agent is baking soda, or sodium bicarbonate.
Buffering transport water keeps the pH from dropping from the acidic affects of carbon dioxide and ammonia. A buffer will also increase total alkalinity as it stabilizes the water by keeping the pH constant.
However, buffering is only recommended in transport water where all ammonia is being bound. If ammonia is not being bound, it is critical that the pH be allowed to drop so that the ammonia is less toxic.
Certain chemicals called oxidizers will react with water to release oxygen. If more oxygen is available, a Koi has to expend less energy to extract it from the water.
Oxidizers may produce oxygen, but many also have been shown to damage the secondary lamellae of the Koi’s gills. In order for gills to work effectively, they contain millions of passages just wide enough for a single blood cell to pass through. Blood cells are infused with oxygen in the narrow passages. An oxidizer can damage the structure of the passages, similar to the damage done by acids. While Koi gills have remarkable healing characteristics, once the damage has reached a certain level, it is irreversible. Any oxidizer used for the period of transport may be doing much more harm than good.
Sedatives and anesthetics, which relax the Koi and decrease their respiration rate, have been used as bag additives. While adding a sedative or anesthetic might initially sound like a good idea, some chemicals that cause sedation in Koi can have unpredictable effects for various reasons such as water chemistry, temperature, size of the Koi and the amount of fat in the Koi. Because drug dose and exposure time are often cumulative, it is difficult to maintain a uniform depth of anesthesia during transport. One reason for this is that levels of anesthesia may continue to accumulate in the brain and muscles even after blood levels have attained equilibrium.
A high initial dose of sedative may stop a Koi from breathing. Another danger, as discussed earlier, is that the use of anesthetics will ultimately depress the metabolic level of the Koi, and they may not be able to expel enough ammonia to overcome ammonia outointoxication, which may be fatal. For all of these reasons, anesthetics or sedatives should never be used as bag additives.
Keeping the Koi in the dark during transport has been proven to reduce stress, and reduced stress means that Koi will be calmer and move less within the bag or tank. A calm Koi will not bang around as much, and will arrive with more slime coat intact.
Additive Conclusions & Recommendations
In conclusion, an ideal bag additive would:
- Detoxify ammonia and chlorine
- Preferentially replace slime coat only where it is missing
- Continuously replace slime coat
- Detoxify Heavy Metals
- Buffer the water such that the water quality parameters are stable during transport
- Treat Osmotic stress
An ideal bag additive would not:
- Risk damaging the Koi’s gills
- Decrease the Koi’s slime coat
- Excite the Koi or increase activity level
- Destroy beneficial bacteria
- Have effects that vary over time, temperature or water quality
- Depress the Koi’s metabolic rate and make it susceptible to ammonia autointoxication
- Any chemical that prevents one problem but causes another, it is not a good candidate as a transport additive.
The ideal shipping system would include:
- Good base water
- Ice packs, well insulated, adhered to the upper sides or top of the container
- Salt at .3%
- Pure oxygen to fill approx. 2/3 – 3/4 of the bag, leaving 5-10% bag space for expansion
- Koi kept in the dark during transport
(If a transport tank is used instead of bags, an air pump with air stone can be used to provide oxygen. All other recommendations remain the same.)