Paul Green of the Ranchu Brotherhood and the Goldfish Society of Great Britain explains why some goldfish experts keep their fish in very shallow water.
Not all adult show quality goldfish are kept in shallow water, but when many varieties are fry/babies the breeders prefer to do so as they believe that at this stage shallow depth will help promote deeper bodies in the long run.
As the fish get older and much body shape development has been completed, it is more common to see them in larger and deeper tanks or ponds. Some of these, in China or Japan for example, are measured in tonnage more like Koi ponds and at this later stage it becomes more a case of grooming.
However, with some varieties like Tosakin their body shape and elaborate finnage means they are unable to cope with deeper depths and the associated pressure.
There is also the phenotype/genotype element to growing on fancy goldfish.The fish may have all the right genetics for a deep body or specific finnage, but if kept incorrectly they may not reach their full potential at the right stage of development.
This item was first published in the September 2009 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.