Caring for your new baby Koi (Tosai)

When you buy small Koi to grow on that are just a few weeks or months old, you need to provide them with the best environment possible if you want them to survive and thrive. If you follow the advice below you will go a long way to doing just that!

When you get your Koi home, float them for around 30 minutes (more if your water is considerably warmer) in the unopened bag on the pond before you release them into their new home. Young Koi have immature immune systems and often need greater observation than more mature Koi to spot if they are having health problems or not.  Other than that, provide your Koi with a clean and healthy environment and good food and they should flourish.  The best growing temperature for Koi is around 23 degrees C.  A temperature of 18 degrees or above will keep their immune system at its most active.

I recommend that you add salt at 0.75% to the system that your tosai are being introduced to as this will help them to settle into their new home.  It helps their osmoregulatory system and also helps them to combat any parasites whilst their immune system recovers from the stress of moving to a new environment.

If a Koi has gone through a period of high stress, then salt at this level can calm the fish down. It also stimulates the production of mucus – the Koi’s external immune system.  Unlike other chemicals, salt is not removed through biodegradation, evaporation or oxidisation and can only be removed with water changes. Salt is a natural product Koi need a level of to survive and, at slightly higher doses, have evolved to tolerate.

Salt, when added to the pond, must be dissolved first as any piles of salt not dissolved can cause chemical burns on fish that might lay in or near it.

Laws of using salt:

1. Only use it when necessary, not all the time.

2. Always dissolve it first when you add it to your pond.

3. Try to bring the salt levels down again as quickly as possible (to 0.02% – 0.05%) with weekly water changes of 10 – 15%.

4. If you are using salt, you must have a salt meter.  You can’t dose properly without one.  If not a salt meter, then a hydrometer.

5. If you don’t have a meter, calculate the pond volume in meters cubed. 1kg of salt per meter cubed is equal to 0.1% salt concentration.  (For example, 30kg of salt is added to 10 metres cubed (2200 gallons) for 0.3% salt.)

6. Don’t use any other medication with salt apart from those recommended by the manufacturer as being safe to do so.  (Especially DO NOT use with Formaldehyde (Formalin))

7. Only use cooking salt or PDV (Pure Dried Vacuum).  Other types of salt can contain iodine or anti caking agents which could be harmful to the fish.

Tip: Chlorine or chloramine are routinely added to drinking water by water utility companies to make your water safe to drink.  These chemicals are, however, toxic to fish so, to be on the safe side, use a de-chlorinator when filling your tank.

NB:  Whilst chlorine will “gas off” if left to stand, chloramine does not.

If you have any questions, please call 01844 217382.