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Treatment Rules

Before adding any treatment to your pond / aquarium or treatment bath:

It can be very worrying when your fish become ill. You may not know where to start, what to do, how to do it, or which product to add to treat the problem. We've created 10 rules for when you have to use medicinal treatments, but be sure to check our Diagnosis Guide and pop into your local NT Labs Authorised Retailer for help and advice to make sure your fish recover as quickly and effectively as possible: 

1. Make sure you have a correct diagnosis of the problem.

Before you can successfully treat any disease it is important to know what it is you are treating. Until you have a correct diagnosis, you will not be able to choose the most appropriate remedy for the problem. Many parasite problems occur because of changes in the water quality. If a disease is suspected, firstly test the water for pH, nitrite and ammonia to make sure there is nothing you need to do before applying the treatment. A partial water change will sometimes cause general improvement in the fish before treating.

It is true that many different parasitic (or bacterial) infections require the same treatment and it is often tempting to put a treatment in the pond just to see if it “does the trick”. While this may work many times, it is not the best thing for your fish or the genreal health of the pond.

To confirm your diagnosis, you should (if you are able) perform a skin scrape to check for external parasites and examine these microscopically to identify them. If you are at all confused or worried, head down to your nearest NT Labs Authorised Retailer and speak to them for some advice.

2. Remove adsorbent filter material.

Nearly all the disease treatments available to fishkeepers have organic active ingredients (even those which claim to contain no chemicals). These organic chemicals are removed by adsorbent filter media such as carbon and zeolite, so remove these before adding a treatment to ensure the treatment is not removed before it has time to be effective.

As a general rule of thumb, the filter mediums can be returned to the filter 7 days after the final dose of treatment has been added, but be sure to consult the instructions to see if the product requires more r less time ot work.

3. Switch off UV filters and protein skimmers.

Ultraviolet (UV) light destroys organic chemicals, which is why they have become widespread as filters. Due to this impressive ability to sterilise water by breaking down organic chemicals, if left on during a course of treatment, the treatment will be destroyed in the same way before it has had time to take effect. Some treatments may even be made toxic by the action of UV light. Switching off the UV during treatment is a sensible precaution. As another general rule, leave UV filters off for at least 7 days (the longer the better, up to 10 days if possible) to give the treatment the best chance of doing its job.

As with active filter media (see point 2 above), protein skimmers may also remove the active ingredient of a treatment before the treatment has had time to work. To prevent this loss of the medicine, turn off the protein skimmer off for at least two hours after medicating. However, proceed with caution: remember that in a marine aquarium, skimmers provide an essential source of aeration to maintain high levels of dissolved oxygen for your fish, coral s and other invertebrates. If you leave the skimmer off for an extended period, be sure to increase aeration to compensate and maintin the dissolved oxgen level in the aquarium. 

4. Increase aeration.

Many disease treaments can reduce oxygen levels but none of them will be harmed by extra aeration so it is best practice to increase aeration if possible, especially you're treating a pond during warm weather. You should also remember that oxygen levels in ponds may be lower in the morning because the submerged oxygenating plants actually consume oxygen during the night when there is no light. For this reason, always leave fountains or other aerating features running 24 hours a day during a course of treatment.

Aquariums will suffer less variation in oxygen levels than ponds, unless they are planted heavily. Regardless of the size or shape, however, it is still best to increase aeration whilst treating the aquarium. 

If the water turns cloudy after a medicine has been added, this may be caused by a bacterial bloom (due to the steps you've taken to ensure the treatment has the best chance possible at treating your fish). These cloudy water-causing bacteria will consume oxygen as they grow, reducing the dissovled oxygen available to your fish, so be sure to provide as much aeration as possible from when you first add the treatment.

5. Only use treatments when you have plenty of time to observe fish.

It is important to treat sick fish as soon as possible after a diagnosis has been made and confirmed. However, bear in mind the time of day (due to the amount of dissolved oxygen available, see point 4 above) as well as the time you have to watch the fish after adding the treatment. Never add the treatment in the pond or aquarium and then go straight off to work or to bed, just in case your fish have a bad reaction to the treatment. Even if you have used the treatment many times before, there is always a possibility that the fish may react badly this time and you need to be there to perform water changes, increase aeration or whatever is necessary to counteract the reaction. Water conditions in aquaria can deteriorate over time so adding treatments may affect water chemistry one time but not another, simply because conditions are different (nitrate concentrations may be higher, GH and KH levels may be low, the pH level may be higher or lower, etc).

In all cases, if you are uncertain of the condition of the water or why a disease requiring treatment has occurred, test the water using one of our mulit-test kits (such as Pondlab 200 Multi-test or Aquarium Lab Multi-Test). It may be that the stress caused by a decline in water quality has allowed the infection to take hold, so you should check your water quality regularly and before adding a medicinal treatment. Performing a partial water change before adding any medicinal treatment is a good idea and will refresh and help improve the environment of your fish. As with all indoor water changes, be careful not to add water with a significantly different temperature to that in the aquarium, or this may stress healthy and ill fish further.

6. Do not mix medications.

The one exception to this rule is products which contain malachite green or formaldehyde only. NT Labs’ Koi Care Malachite and Formaldehyde can be used together, but for your convenience we have formulated a product which already mixes these at an appropriate and safe dosage: please see our FMG Mixture for more details.

We do not recommend mixing any medicinal treatments (except those listed above), particularly where the products are from different manufacturers. Netiher you nor any of the manufacturer's will know of the cumulative, unpredictable or potentially dangerous effects the mixture/s may have, and we will only be able to offer you a "best guess" as to how your fish may react. It is far better to stick with one manufacturer's products one at a time, as they will be able to fully advise you on the problem. But you still shouldn't mix them!

During our time at NT Labs, we've heard lots of myths which are widespread but for which there is no scientific basis. One of these is never to use Formaldehyde when there is salt in the water. The only unsubstantiated theory we have heard about why this should be is that the presence of salt will make the formaldehyde come out of the water as a gas? This seems unlikely to us, since formaldehyde is used in marine aquariums where the salt level is very much higher without any problems. We can find no scientific reason not to use formaldehyde when there is salt in the water.

7. Wait at least 7 days before using a different medication if no improvement is seen.

Allow time for the treatment to have an effect and to break down naturally and perform a partial water change before adding another treatment which may react with the first. If no improvement is seen after the first treatment, check the diagnosis and make sure that the dose you added is correct and the treatment is the most appropriate.

For example, malachite green and formaldehyde are not appropriate treatments for skin and gill flukes, fish lice or fin-rot. Although they may help by removing any skin parasites which could be aggravating the problem, the main symptoms will remain and require treatments such as FlukasolPermanganate Dip and Acriflavin for your koi pond.

Examining a skin scrape under the microscope may reveal skin parasites and flukes together. If this is the case, you will need to judge which problem is more severe (in this exmple, the flukes or the parasites) and treat this problem first. If you see a multitude of different parasites in a skin scrape, the best treatment may be a simple water change as such a mixture of diseases indicates poor water quality, unless you have added new fish without quarantining them. When you are dealing with a parasitic and bacterial infection, it is generally more productive to treat the parasites first, as, once dead, these external parasites will often leave small open wounds where they have penetrated the skin which are at risk of subsequent infection. This way, the number of anti-bacterial treatment courses required will be reduced, but if the bacterial problem is the most pressing, treat this first.

8. Beware of water temperature.

Adding a treatment to a pond where the water is very cold will probably not do any harm, nor will it do any good. At low temperatures, the metabolism of parasites, bacteria and fish alike will be lower, which is why fish feed less in the winter (coupled with the fact that they are generally much less active in the winter than in the warmer months). Similarly, medicinal treatments will react slower in colder water, and with the parasite's metabolism unlikely to break down enough of the chemical to kill it, the fish are unlikely to significantly benefit from treatments performed during cold weather.

We recommend not treating a pond if the water temperature is below 10°C (50°F). Of course, if the situation is critical and the fish look unlikely to survive without treatment, you must treat whilst the water is cold.

Conversely, if the water is very warm, it has a reduced capacity to hold dissolved oxygen. Adding a medicinal treatment may reduce the amount of dissolved oxygen even further, and may result in your fish suffering from oxygen stress and exacerbating their original disease/infection.

We recommend avoiding treatments when the water temperature is above 25°C (77°F) in ponds. However, if the situation is very urgent and nothing can be done to reduce the water temperature (such as a partial water change, shading the pond, etc), you must treat whilst the water is hot, but be sure to provide extra aeration during the course of treatment and keep a close eye on how the fish are coping.

Aquarium treatments are designed for use at a higher temperature and at the tolerance levels of active ingredients which we know are acceptable. DO NOT use pond or koi treatments in aquarium. If you do, you put your fish at risk of a significant delpetion of oxygen (as higher temperatures reduce water's oxygen holding capacity) and an overdose of the medication (as our Pond and Koi Care products are designed for outdoor use in large bodies of water, variables which cannot be replicated indoors). Be sure to observe fish regularly during the first 12 hours of treatment in an aquarium, as the risk of overdosing medications is much higher, water quality is more variable than in an outdoor pond and the risk of oxygen-depletion is greater.

9. Feeding

Generally, it is fine to feed fish whilst they are undergoing a course of treatment, as long as they are still eating. However, always follow any specific instructions regarding feeding given on the label of the treatment, and do not be tempted to overfeed. If the fish are very ill and don't seem to be eating much anyway, it would be best to stop feeding for a few days at the beginning of the course of treatment until the fish have recovered their appetite to avoid reductions in water quality. In general, NT Labs’ food products neither react with treatments nor affect filters and fish can safely be fed whilst there is treatment in the pond or aquarium. Please be aware that uneaten food will degrade and may pollute water reducing water quality, so if fish are uninterested, do not feed.

If, however, the biological filtration system should be damaged by the addition of a treatment used incorrectly or a medicine that affects filter bacteria (all NT Labs' products are filter-safe at their working concentration), feeding the fish could cause nitrite and ammonia levels to rise, leading to a reduction in water quality and causing stress to fish. Check the water regularly during treatment, and throughout its life: regular, routine testing of the water will show the natural cycles in your pond, and can help you diagnose and fix a problem before it affects your fish. Monitoring your water during treatments will also allow you to see if the filter bacteria have been damaged by the treatment, and you can choose the appropriate filter bacteria product to help the filter recuperate.

10. Follow the instructions on the bottle label.

This is perhaps the most important rule of all. All veterinary medicines must have the dosage rate and instructions printed on the bottle label under Veterinary Medicines Regulations. Always follow these instructions, measure the dosage carefully and do not be tempted to put a bit extra in for good luck. 

By following these rules, you should be able to treat your fish without a problem, but "prevention is better than cure" as the saying goes. Regular monitoring of your water quality (testing for ammonia, nitrite, nitrate, pH, KH and GH) will allow you to forsee any problems that are often caused by poor water quality. Sometimes a simple water change is all it takes to stop a disease or infection taking hold, and regular testing may save you a lot of time and headaches in the long-run!

Tagged in: Indoor, Outdoor