Resistance

Because medication is so frequently used in our hobby, we face persistent resistance in all sorts of areas. Resistance can be described as a hereditary acquired resistance to toxic substances. Most "medicines" we use for our ponds are nothing more than poisons, the goal being to administer enough doses to kill the parasite and keep the host alive. You understand that using these substances can also be quite damaging to our fish and the pond environment. Partly for this reason, I'm always cautious when it comes to treatment. I prefer to optimize the fish's living conditions, allowing them to build up a good resistance and control the few parasites that occur in every pond. Of course, it can happen that medication is unavoidable.

Acquiring resistance

Every organism that reproduces has a unique DNA code, even single-celled organisms that multiply through cell division. Errors are always made when copying DNA. For example, when you use a certain dose of antibiotics (a drug against bacteria), there are always a few bacteria that, due to these random errors, are more resistant to the drug. If these survive the treatment and begin to multiply, a population of bacteria is created that is resistant to the previously administered type and amount of antibiotic. Especially with small parasites, the multiplication rate is very high, which can quickly lead to a resistant population that is just as large as before the antibiotics were administered. You will then have to resort to a stronger or different drug. If these resistant bacteria then end up in other pools, the drug will ultimately no longer be effective. In the human world, consider MRSA, the hospital bacterium, against which antibiotics are virtually no longer effective. A major problem! Therefore, restraint in the use of antibiotics is appropriate. In my opinion, randomly injecting antibiotics for a bacterial infection is a bad idea. It's gambling and promotes resistance. The right approach is to make a culture (via a swap) to establish an antibiogram aimed at prescribing an effective antibiotic. Much better than gambling!

Worm remedies

Besides antibiotic resistance, resistance to skin and gill fluke medications is a major problem in the koi hobby. Many medications are no longer effective or require much higher doses. An arms race has developed (newly developed medications versus resistant worms), with the worms seemingly winning. Sometimes, up to three treatments with different medications are needed before the one that works is found. Sometimes even that isn't enough. To maximize your chances of success, here are some tips if the first treatment isn't effective:

• Change 30% of your pond water.
• First, use a product like potassium permanganate (KP) to "strip" the fish's mucous membrane. Caution: this is a dangerous product, and your own health is paramount. Seek expert advice or assistance, and wear skin, eye, and respiratory protection. By "burning" away the mucous membrane, a significant number of worms will be released, making the remaining worms more accessible to the worming agent.
• When using a powdered worming agent, it's essential to thoroughly dissolve it before administering it. Ideally, first dissolve the powder in acetone or rubbing alcohol, then add it to a watering can of warm water and spread it throughout the pond. If you don't have or prefer not to use rubbing alcohol or acetone, dissolve the powder in warm water with a dash of dish soap (this will make it dissolve a little more easily). Stir well with a whisk or similar! Use the worming agent a day after the NP, otherwise the slimy layer will have returned.
• If you use a drum as a pre-filter, there's a risk that undissolved powder will be quickly filtered out. Therefore, stop the drum for the first few days of treatment and use the bypass (remove the red caps in the drum to allow the water to flow through by itself).
• Turn off UVC lamp, remove absorbing materials such as activated carbon or zeolite.
• Do not change the water during the treatment. Change 30% of the water after the prescribed period.
• For gill flukes, repeat the above process, starting one day after the water change. Gill flukes lay eggs, and these eggs are immune to the worming agent. The second treatment should kill any worms that have already hatched.

Author: Joop van Tol (www.koitoday.nl)