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05 October 2017
How many fish can I have in my pond?

How many fish can I have in my pond?

It is important to ensure a pond is not overstocked as it can be harmful to fish health, as well as resulting in a dirty and un-attractive pond.   To calculate the volume of the pond you simply need  to  do the following calculation:

Length x Width x Depth x1000


i.e. The volume of a 3m x 2m x 1m pond is calculated with the equation

3x2x1x1000 = 6,000 Litres


Remember this calculation is only for metric units you must convert feet into metres before you do this.


As a general rule you can use the following guidelines for suitable fish stocks: 

•  Average fish pond (e.g gold fish) – 3kg of fish per 1000 litres of pond water e.g. 4000 litre pond will support up  to 12kgs of fish


•  Koi pond allows for 1kg of fish per 1000 litres of pond water e.g. a 4000 litre pond will support up to 4kgs of Koi  

Remember Koi are much dirtier fish and produce a lot more waste.  This means that they need a better level of filtration and normally cost a lot more to keep.   Koi ponds should also be at least 1m deep over 40% of the surface area.

My fish have a disease, what should I do?

Fish Diseases

Fish Diseases can vary greatly in type as well as severity.  As a general rule it is important to keep water quality as high as possible which will avoid the majority of diseases.  The water can also routinely be treated with a General Tonic and Pond Salt which will also help to combat any diseases.

 General Tonic – This contains formaldehyde and the tonic should be used as a general treatment whenever the fish are stressed or the water quality is poor.  It can also be added monthly to prevent other fish diseases that derive from parasite, bacterial, or fungal organisms.  Good times to use it if only sporadically being used is in the spring to help fish recover from the winter, when introducing new fish to the pond or after a water change.

 Pond Salt – This is literally adding salt to the water.  Many pond keepers simply use kitchen salt, although specific pond salt is better.  This addition helps to boost the fishes immune system which allows it to cope with diseases themselves.  The level of salt which should be added changes according to the reason.  It is important not to put too much in as this can do harm to the fish.  Just in the same way putting them in sea water would do.  A rough guide can be seen below based on the Blagdon Pond Guardian Tonic Salt.  Once the salt has been added it will remain in the water indefinitely unless removed via some method of water change.

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