Coldwater fish are fish that prefer to live in cooler water temperatures typically below 20*C, so therefore they do not require a heater in their tank. These fish can also live in outdoor ponds, but they must be kept indoors during the winter.
These fish tend to grow slower than tropical fish that live in warm waters, but they are also quite hardy. Coldwater have longer livespans and are quite easy to keep with some basic maintenance. The most common coldwater fish are goldfish and koi fish.
Goldfish are available in many sizes, shapes, and colours and it took breeders many centuries of selective breeding to create the countless different varieties of goldfish that we see today.
Common goldfish that can live in ponds are London and Bristol Shubunkins, Jikin, Wakin, Comet and some hardier fantail goldfish. Plants are essential in a pond as they act as part of the filtration system, as well as a food source for the fish. Plants in a pond also help to raise oxygen levels in the water for the fish to survive.
During winter, goldfish become sluggish, stop eating, and often stay on the bottom of the pond. This is completely normal; they become active again in the spring. A filter in a pond is important to clear waste and keep the pond clean.
Lifespan for Coldwater Fish
The lifespan for Coldwater fish like Goldfish & Koi is up to 10 years if they are carefully looked after.