Guidelines for fish stocking levels vary from different bodies of expertise. However, as a member of OATA (Ornamental Aquatic Trade Association) and having a team of aquarist experts within Blagdon, we believe that the key to keeping fish healthy is good water quality and space to swim. This includes good oxygenation that comes from surface area and circulation.
Firstly, what stocking level gives the fish space to grow and move about freely?
Secondly, what would happen if there were a power cut and the ‘life support system’ was off? The balance is stocking the pool to a level where, should the power fail, the fish would survive for an acceptable amount of time to allow the owner to return and address the problem.
A general rule of thumb is not to stock more than 60cm of fish body length (not including the tail), per square metre of surface area of the pond.
To find out the surface area of your pond, multiply the average length by the average width.