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Potassium permanganate

It is a general misconception that potassium permanganate is dangerous to use for fish. One vet would warn "very strong and dangerous...it burns the gills and we do not recommend" while another vet cannot stop singing its praise as "extremely effective".

What the normal koi keeper hears is "don't use it...it is dangerous"

In fact it is just the opposite.


Media Retainers and Fish Cages

Media Retainers and Fish Cages

Moving bed filters offer various solutions for the problem of retaining the moving media in a place without restricting the flow and preventing loss of media. At a high flow rate, a simple grid at the exit point is often not good enough to avoid this from happening. A retaining grid that meets the requirement of a specific media is need. We approach the problem in a slightly different way.


Diffusion Depth

Media and the Diffusion Depth of the Biofilm.

The diffusion depth presented impacts on the evaluation of removal rates and treatment performance of MBBR carriers (biofilm media). Dr. Markus Geiger and Bernd Rauch from Multi Umwelttechnologie AG discuss important aspects to consider.


Jumping and swimming speed

Jumping fish and swimming speed

Many koi owners have experienced a fish flapping on the lawn because it jumped out of the water. Many have spent fruitless hours trying to revive these suffering fish in the hope of a miracle happening.  We want to blame someone for this mishap and are quick to find the culprit, usually a protection net that was carelessly closed over the tank, or worse, failure to use the net at all. They call that negligence.


The Making Of Colour

 In a colourful world

While the morphological variation was important in the creation of koi as they are today, the expression of color is certainly central to defining koi as ornamental. It is true to say that without colour koi would never have developed. Skin pigment cells produce the various colors. Erythrophores and xanthophores contain carotenoid pigments and produce various shades of red or yellow. Melanophores are black and contain melanin.


Mutag BioChip vs Kaldnes K1

Mutag BioChip vs Kaldnes K1

In a recent study, Bassin et. al. (2016) assessed the activity of the suspended and attached biomass on two types of moving-bed biofilm carriers under identical conditions. The moving-bed biofilm reactors were loaded with K1 (MBBR1) and white Mutag BioChip™ (MBBR2) and evaluated at different pollutant loads.



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The Angle of View

The Angle of View

In our hobby the body shape of a fish tells us much. The concerned hobbyists try to gauge the sex, the age, future potential and quality from what they see.  When looking at photos however, it is easy to form the wrong impression. Be careful to judge too quickly.

When viewing photos of fish, one must be aware how serious the angle of view can effect the photo.


Terms & Conditions

Terms & Conditions for Live Fish

We have been involved with be business of importing and supplying Japanese koi to hobbyists countrywide since 1995. We understand the nature of fish and how to keep them stress-free and happy. We offer a limited guarantee subject to the following Special Conditions to the live fish we supply.
The fish is sold "as is" and KoiNet cannot be responsible for any innate condition the fish may have. We understand our responsibility to maintain our stock of live fish in a healthy condition and deliver such fish to you, the Customer. We do not shy away from our responsibility.
You buy live fish from KoiNet on that express condition that once the fish is placed in your hands, the risk and responsibility passes to you. It is your responsibility to provide adequate care for their wellbeing and survival. We cannot control the conditions under which you place the fish and cannot accept responsibility for your actions.
Live fish cannot be returned to us and will not be accepted for return delivery from any party. If you have a valid claim and/of were misled in some way, we may offer a replacement, or discount and try to come to an amicable agreement, but for biosecurity reasons fish cannot be taken back and sold to another customer. It will either be destroyed or we need to come to an agreement which may include the option for you to keep the fish.
Fish are guaranteed for a period of 5 days after arrival in the country if pre-paid import orders, or 5 days after delivered to us from a local source. This guarantee is carried by our supplier and it is for KoiNet to communicate with the supplier should any problems arise. Shipments of fish are either delivered directly to the client or maintained in our quarantine system where they will remain for a minimum of 7 days. While in quarantine the are prophylactically treated for parasites. They are also stress-tested for signs of known viruses which is then laboratory identified if needed. While in our care we take full responsibility for their safekeeping and health. When delivered from our facility such fish carry a 5-day guarantee from date of delivery to the client.
Despite this guarantee you are to keep records and photos to substantiate your claim and must be able to provide detailed record thereof. Any claim will be relayed back to original supplier. We/he will endeavor to compensate you for any losses should it can be proven than the fish were NOT in contact with third party fish for the entire period or this guarantee and that proper precautions were taken against pathogens. All dead fish must be photographed, photo’s date-stamped and fish kept in a freezer until the claim is finalized.
This guarantee is limited to suppling a fish of equal value excluding the costs involved with transport and delivery to you.

Failure to provide proper records and failure to contact KoiNet immediately will render this guarantee or subsequent claim null and void. Our supplier and breeders prescribe these conditions and we to not argue.
We buy directly from the breeders with whom we have built a close and trustworthy relationship over the years. We have been with our Japanese agent since 1995. We deliver the best koi for their price and we endeavor to maintain that standard. KoiNet is not the breeder, and can never be responsible for the performance of the fish as they age. Whether quality improvement or degradation; growth or growth rate; colours fading or improving; develop deformities or any other condition of an innate or genetic origin.
This guarantee cannot be enforced while the fish is in the hands of a third party and while KoiNet cannot control the handling of the fish. The customer must accept that he is buying a living organism with all the uncertainty that it brings, and that he accepts full responsibility, and barring mishandling, negligence, accidents and mishaps on our part, he has no claim against KoiNet.
KoiNet endeavors to take all the precaution necessary to deliver a healthy fish to the customer. We are experienced in in fish keeping and will not do otherwise but care for the wellbeing for fish in our care. That is our priority - to deliver a healthy fish to you.

2013, Updated July 2017

Showa or Sanke

Showa or Sanke, what is in a name?

By Jim Phillips (SAKKS)


What's in a name? That which we call a rose,

By any other name would smell as sweet

William Shakespeare 1595 Romeo and Juliet. Act 2 scene 2.



EkoSlim Turns 339%

Development over the past few years by KoiNet on the applications of airlift technology has led to a range of aquaculture products inter alia:

  • EkoSlim Water Pump
  • EkoSlim Inline Water Pump
  • EkoSlim In-Pond filtration
  • Custom filtration Systems
  • Mobi Tank
  • EkoSlim Heater and UV


RAS Systems - Super Filter Media

The Mutag BioChip™ media for moving bed biological filters.

Aquaculture professionals, breeders and koi communities use Mutag BioChip™ as biofilter media for best water quality and large savings on OPEX

The Mutag BioChip™ speeds up pond filters with 3,000 m² of active surface area per m³ of filter media for the steadily growing nitrifying microorganisms for reducing the ammonia which is produced by the fish.


Fish Genetics - a good book

Fish Genetics: Theory and Practice

by Boris Gomelsky

This book is written in textbook format and presents an overview of different aspects of fish genetics in an understandable and systematic style.