Veterinarian Tim Barbé

KOI, your passion
my specialty!

Sending a sample to the lab

I want to send a sample for analysis in the fish lab
In our lab we not only test the samples collected on the day rounds but we also receive samples sent to us from home and abroad, both from professionals and individuals.
Would you like to have a newly purchased fish screened for KHV, CEV? Do you have a problem in the pond and want to have it checked to see if 1 of the germs from our range plays a role in the disease process? You can! But then it is important to consider a few requirements:

– The diagnosis can only be as good as the quality of the sample. That is, the sample must first and foremost be taken correctly. Next, the sample must be properly stored and shipped. More details are described below!

– Interpreting results is not always so obvious or simple. The terms used or knowledge of whether or not pathogens can be found in the sample is not for everyone. Therefore, preferably have a veterinarian assist you.

– We act as an intermediary, we can give advice on which test is possible and useful, explain the results but do not initiate treatment as a result of our findings.

– If the sample is a swab for “microbial culture with antibiogram”, it is essential to include the referring veterinarian on the form and his contact information! He can interpret the results and convert them into a targeted treatment. For example, he knows what it means if a germ is intermediate sensitive and if a treatment can be set up for it. Knows the names of the different molecules mentioned on the report and how to apply them and at what dose.
– If our veterinarian has to go and do this interpretation for you there will be an additional charge. Antibiotics cannot be freely delivered by law without us examining the animals!

– Before we will publish the results of analyses, the costs must be received on our account! For a smooth process: always let us know when samples have been sent, if necessary mail us already the anamnesis form (you can download it here on the site). Once the samples are received we will then send you confirmation of receipt with the invoice. Depending on the turnaround time of the requested analysis(s), you will then have at least 24 hours to deposit the money and provide proof of payment if necessary.

– We are sent several samples, without the anamnesis form we cannot know exactly what is expected, who the sample is from and to whom the results should go!

– Keep in mind that samples sent through the mail may take a while to arrive and at worst may be lost or damaged. Make sure you have proper postage, strong material and proper packaging (a swab in a standard envelope with 1 stamp might get damaged in the postal sorting machine!) Samples from the Netherlands sometimes take a week to arrive!

How to take a correct sample for further analysis!?
The most appropriate person to take a sample correctly is a veterinarian specializing in fish. We sometimes receive pathetic samples, for example pieces of gill stuffed into a bacteriology feeder for a test for KHV. We repeat that the diagnosis can only be as good as the quality of the sample! Also know that 1 finding from the study need not be all-encompassing. A fish that has CEV can also be KHV positive! The

The disadvantage to a single-PCR is that you’re going to be looking so specifically at 1 pathogen but many disease states, and especially in summer, are multifactorial.


For analyses by PCR, it is important that we receive intact DNA. After death, proteins and tissues denature and thus just break down (spoil). Therefore, it is important to collect samples for PCR preferably within 24 h of death. You also put the sample in alcohol of at least 70° (ethanol, isopropanol). Per test we only need 40mg so a small piece of tissue in a small tube with a small amount of alcohol is sufficient. You may combine up to 2 fish in 1 sample, for example a piece of gill from 2 koi together in 1 tube. For screening, it is useful to find out the status of 2 fish simultaneously. With illness, you may have samples of 1 fish that was euthanized because it was too sick but you have another fish with symptoms that you can also add a piece of gill, for example. For disease processes, always take a sample from a fish with symptoms, even if you have KHV in your pond, healthy-looking fish can test negative!

Any jar or tube that closes properly can serve as a container. Of course, make sure it is clean at the start. Disinfecting alcohol from the home pharmacy is fine as a preservative.

Microbiological examination
The purpose of a swab is to use it to touch those bacteria that are currently invading the skin of your fish. Just like on our skin, bacteria are always found in healthy fish, including Aeromonas type bacteria. Once a fish’s skin is no longer intact, environmental bacteria can no longer be shed, making a wound a breeding ground for all kinds of bacteria simultaneously. Creating a culture of a

swab therefore does not always reveal the correct causative bacteria. Preferably insert the swab deep into the skin at the edge of a lesion. Often your fish have lesions in several places, in that case sample the most young active spot where the bacteria are still in full growth without taking dirt and dead material with them. It is of course important that the swab is sterile before you drill into the skin of your fish with it and that you also sample the swab in only 1 location. We definitely recommend taking 2 separate swabs in case of hole disease. Preferably from 2 different fish. We put both swabs on culture, interpret them and proceed with these that appear to play a role in the disease process. Do not drop a sterile swab on the ground, do not accidentally dot the pond water, do not dot the center of a wound or really in the rot of a necrotic gill. Such issues can negatively affect results.

Swabs can be obtained from your doctor, veterinarian or sometimes at the pharmacy. These should be sterile and contain transport medium to keep the germs alive during transport! If necessary, look at the photo to see an example of an appropriate swab.

Water Analysis
We usually receive samples for determination of (heavy) metals (Cu-Fe-Zn). Most of the parameters are best determined with a standard test kit at the pond because parameters such as oxygen, ammonia, nitrite can still change in the container under the influence of biological processes taking place in the sample. The warmer the water, the faster changes can occur. If the steel can be kept cool then it is not too bad. Per parameter to be tested, 25ml of water should be sufficient but preferably provide some extra reserve.

We are also sent water for germination pressure determination. For this we do not need a lot of water but it is especially important that you go to take the sample at a time when there has been no disturbance in the pond and on an average day. Not if, for example, the filters have not been drained for weeks, not even after refilling the pond, not during treatment with disinfecting products, not if the pond has just been stirred up considerably, resulting in the stirring up of silt,…
A sterile jar is most appropriate. Alternatively, you can buy a new sealed bottle of drinking water from the supermarket (33cl or 50cl for example), pour it empty and fill it at once with pond water (airless) and send it off. For toxicological testing, at least 1 liter of water should be available and should be brought in together at the Faculty of Veterinary Medicine of UGent.

Anamnesis form