Do Koi Fish Only Grow as Large as the Size of the Pond Allows?

Just like many other activities enjoyed and practiced by people around the world, the fish keeping hobby isn’t immune to misconceptions, myths, and urban legends. One such falsehood tends to be centered on goldfish and koi—two ornamental freshwater species that have been subject to crossbreeding for centuries. There’s a good chance you’ve heard about koi and goldfish, which both happen to be related to Asian carp species, somehow being able to control their growth and adapt to the size of their enclosed ecosystems. In other words, this incorrect assumption suggests any goldfish can be kept in a small fishbowl. As for koi, this inaccuracy posits that koi won’t get any larger than what their ponds allow. Here’s what you should know about koi growth, brought to you by the pond experts at Aquatic Warehouse, a leading provider of koi pond supplies.

Fish Grow According to Genetics

All aquatic species are born with a set of genetic factors that determine their sizes at various stages of physiological development. Within these genetic factors, there’s a range that runs from average sizes to their largest growth potential, which can be achieved under certain conditions. It’s very likely this biological fact has been misconstrued to suggest koi will only grow as large as their ponds. The reality is that a pond that’s too small or overstocked will prevent koi from reaching their maximum growth because constrained swimming conditions don’t promote healthy development.

Stunting Versus Adapting

Koi are cold water species that have become highly adaptable through selective breeding. When this species isn’t able to achieve its maximum growth, a stunted growth phenomenon will occur, but it shouldn’t be confused with adaptability. Stunting happens when the fish skeletal system stops growing while the internal organs continue to develop more tissue. As can be imagined, this is an unhealthy and painful condition for koi, and it may result in lower quality of life as well as a shorter life span.

Recommended Pond Size for Koi

If you take into account the median size of koi varieties, the smallest pond should hold at least 1,000 gallons of water with a minimum depth between 2.75 to 3 feet because of the accessibility from predators. You shouldn’t raise more than two koi unless the size of the pond can hold more than 1,500 gallons. However, you can never have a koi pond that’s too large. All aquatic species appreciate being able to swim in habitats that provide plenty of space.

Getting the Right Koi for Your Pond

If your garden can only accommodate a 1,000-gallon pond, you won’t want to get Tosai varieties that are known to easily grow beyond 30 inches. Shubunkin typically reach a maximum length of 10-14 inches, and they’re very friendly. Doitsu butterfly koi are very beautiful and carefully bred so they’ll rarely grow larger than 10 inches. The Gin Rin Showa variety is among the tiniest, and it’s known for its sparkly scales.

In addition to having a pond that’s large enough to accommodate your koi, you need to make sure you have all of the necessary supplies to maintain the pond properly and keep your koi happy and healthy for many years to come. From pond vacuums and filters to beneficial bacteria and nutritious koi food, Aquatic Warehouse has everything you need. Stop by our store in Kearny Mesa, order your supplies from our website, or give us a call today at 858-467-9297 with any questions.