As prominent members of the carp family, goldfish contain the genetics for very large growth. There are many giant goldfish claims that actually turn out to be orange koi, a very close cousin of the goldfish. Depending on the goldfish type in question, how big do goldfish get?
How big do comet goldfish get?
Comet or common “feeder” goldfish have the greatest potential for large growth. Yes, these include those fish given out at fair events. Many carp species, including goldfish and koi, have almost exponential potential for growth throughout their lives, depending on their access to life resources such as space and food. Restricting your fish’s space to “the size of their container,” is the same as stunting. This also applies to withholding food to improve maintenance or limit growth. Your fish can be fed regularly, just with a lower protein diet, and still maintain their overall health and wellness. Do not use your laziness in doing proper maintenance as an excuse not to feed your fish.
In captivity, we have seen comet goldfish grow up to the size of a dinner plate (14″). Meet Silverado:
This comet had his own 100 gallon tank to accommodate his large size. He was in his teens when he passed away. Other than a mass next to his eye and some wavering water chemistry, he had a very good life. But he is a prime example of one of those little fair goldfish thriving at life.
How big do goldfish get in a pond?
Many goldfish living in outdoor ponds can get very large as well. Access to lots of food and space usually allow goldfish to grow a foot long or more. Ponds mixing koi and goldfish and feeding high protein or growth food often leads to goldfish being mistaken for koi.
How big do fancy goldfish get?
Depending on the variety, fancy goldfish can also get very large, but not as large as long-body, comet goldfish. We have seen a Ryukin 10″ long and almost the same circumference. Due to their genetic restrictions, most fancy goldfish do not get larger than 6-8″ long, which may or may not include their ornate fins.
When growing monster fancy goldfish, extreme caution should be taken in making sure they grow slowly. Sudden growth can cause buoyancy disorders where their swim bladder cannot accommodate their mass and lead to common fancy goldfish buoyancy disorders.
What is the record for largest goldfish?
Most of the “Largest Goldfish” records are actually koi, a different species from goldfish. The world record for the longest goldfish was set for 47.4 cm (18.6 in) in March 2003.
How do I make my goldfish grow to full size?
Depending on your fish’s genetics and life history, they might not grow to the size you expect. Certainly, most goldfish could potentially grow to a foot or more, but nothing is guaranteed. For all fish, be sure to provide the right environment and diet for the best life possible.
The easiest method to ensuring the health of your goldfish is to provide a bigger and better environment. Upgrading from a horrific bowl to a filtered tank has brought about our most dramatic changes in goldfish size and appearance. For small goldfish, a tank size of 20-gallons per fish MINIMUM often requires upgrades to significantly larger tanks (see one fish in 100-gallons above). For most fish, including goldfish, the bigger the tank, the better.
A bigger tank is not always beneficial for fancy goldfish. Many fancies, with a precarious grasp of neutral buoyancy, can have issues with tank upgrades that are significantly deeper than their previous tank, causing increased hydrostatic pressure and buoyancy issues. Fancy goldfish do not do great when having to swim large distances, such as in outdoor ponds, and may benefit from a more controlled environment with less drag and pull on their long fins.