Keeping Fish: How Many is too Many?

Keeping Fish: How Many is too Many?

By Megan Saba / January 17, 2019

Like any eco-system, water gardens need to be in balance. A good balance of water, flora and fauna will result in a healthy ecosystem. However, water gardens that are out of balance suffer from many problems, many of which can be attributed to an overpopulation of fish. Fish are a wonderful addition to a water garden. Fish not only add to the aesthetic of your pond with their color and beauty, they also are often loved by their owners they interact with and can have health benefits by helping to reduce ailments such as high blood pressure. When adding fish to your pond, remember the important balance. When selecting your fish, it’s easy to get too many when the fish are young and small. It’s important to remember that a healthy fully-grown koi can reach lengths of almost two feet with proper care. It is also believed that fish will only grow as large as their environment will sustain, this is absolutely untrue and can lead to problems as the fish mature. A water garden with too many fish easily gets out of balance from the excessive fish waste deposited in the water which can lead to murky water and algae blooms. Furthermore, overcrowded fish are often stressed which can cause aggression, and suffer increased incidence and spread of disease among the population. So, how many is too many? The first step is to know how many gallons of water your pond holds using this easy formula: Length x Width x Depth x 7.5. Once you have the volume, the general rule of one koi or two goldfish per 250 gallons of water is optimal for a healthy balance. So, if your pond holds 1,000 gallons, it can safely sustain 4 Koi or 8 goldfish. Be sure to have some type of filtration as well to keep the water clear. Finally, avoid over feeding your fish. Generally, feeding only as much as the fish can eat in 5 minutes every other day is sufficient. Floating fish pellets, make it easy to monitor how much your fish will eat and provide balanced nutrition. Keep your mini-aquatic ecosystem balanced by following these simple guidelines and have happy and healthy fish as well as clean and clear water.