Loseing Koi Carp

[welshboy]

Hi' Yesterday morning i saw my large koi carp flooting on the water.When i had a look at the fish i found no markings, the gills were nice pink.I had the fish for 10 years, i don't know if it died of old age it was 20''long and 3 pounds in weight.Mark

 

[mark4785]

Hello,

I'm sorry to hear about what has happened, it must have been a shock.

In order to establish how it has become deceased you should go about testing your nitrite and ammonia levels; anything above zero can cause significant stress to Koi. I think the most important water component to test for would be the PH and KH (Carbonate Hardiness) levels of your pond. KH is a measure of the buffering capacity of the water to resist changes in the PH level; the lower the KH the more likely your PH will change dramatically, causing immediate death to fish. "PH crashes" often occur over night for numerous reasons so providing your KH level and PH levels are inadequate, I think this will explain why the fish was found deceased by the morning.

PH and KH levels can be tested using commonly available pond water testing kits; the most popular and accurate brand is API.

If your PH is below 7.0 or above 8.8 go about making adjustments so that you attain a level of 7.5-8.5 as Koi like moderate alkaline water. PH levels should not fluctuate by more than 1.0 units per 24 hour period.

If your KH is low, go about increasing it substantially to avoid further PH crashes.

I hope this information is of some use,

Mark.

 

[Haych]

sorry for your loss

obviously it is a very good idea to test your water levels to ensure it isnt that - but just to let you know that my sister has lost around 10-15 koi this winter due to the drastic changes in weather

They are all quite poorly (the koi more so than the goldfish) and when they took them to an aquarist shop they told my sister it was due to the severe changes up and down in the weather stressing the fish and killing them

My sisters have white slime, popeye, and their natural slime missing too because of this

 

[Duck and Dive]

Redning round the gills can be caused by a nitrite spike. So I would test the nitrite (NO2) levels, or better test all the water parameters. I have seen this in a pond before but it never killed them, so the concentration of nitrite could be very high. Do you switch your filter off over winter?