Freshwater fish are typically split into 3 categories; Cold-water, warm-water, and cool-water. It is important to select the category of fish that will thrive in your type of pond and in your geographic area. The major limiting factor with the temperature is the amount of oxygen in the water. Cold water can hold more oxygen than warm water. Cold-water species require higher oxygen levels that are often associated with the colder water temps.
Cold-water Fish
As the name implies, these are species that require cold water to survive. Trout are the most common cold-water species used in ponds. Trout ponds are limited to northern portions of the country or high elevation areas where air temperatures can support the colder water. Coldwater species typically grow best is water that is in the 50’s and 60’s degree Fahrenheit range. It is also important to have proper depth ponds to maintain cold water areas. The minimum oxygen level for these species is typically 5 PPM. When levels drop to 2-3 PPM, it is lethal on cold-water species. Also, the bigger the individual fish, the higher the oxygen levels need to be to support life.
Warm-water Fish
Fish that thrive in warm water conditions are the ones that typically come to mind for most pond owners. These would be Largemouth Bass, Catfish, Bluegills or Sunfish, and Crappies. These fish are typically hardy throughout most of the US and can survive winters in the north. They grow best when water temps are in the 80 degree range and require 2-3 PPM oxygen levels. Levels of 0.5-1 PPM are lethal for warm water species.
Cool-Water Fish
The third group is considered cool water species. These would be Walleye, Musky, Pike, and Yellow Perch as the most common for ponds. These fish fall in between the other two groups and can handle warmer water conditions than Trout, but cannot handle the extreme heat as the warm-water species can. You will typically only find these species in the northern and midwestern areas of the country. They grow best when water temps are in the 60’s and 70’s. They require a minimum of 4 PPM of oxygen and levels around 2 PPM or less are considered lethal.
Choosing Fish for Your Pond
Since they offer the most versatility, warm water fish species are by far, the most commonly stocked pond species. Most ponds will do well with a combination of warm-water forage and predator fish. If you are in the upper Midwest or northern portions of the country, you may also be able to incorporate some of the cool water species into your pond mix. Pike and Yellow Perch are the most common, followed by Walleye in some instances.
Trout or other cold-water species are really only practical in extreme northern ponds or in ponds that have significant natural springs or flow through. Deeper ponds may also be able to support cold-water species as well.
Again, it is recommended to talk with a local lake manager, DNR agent, or Extension agent to formulate a plan for what species with work in your pond.
Below is a chart showing typical dissolved oxygen consumption for the different groups of fish. The numbers are in pounds of oxygen per 100 lbs. of fish per hour. The colder the water, the more oxygen it can hold. Aeration is important, but if the water is too warm, it still will not sustain cold-water species.
Cold-water Adults .02
Cold-water Juveniles .03
Cool-Water Adults .025
Cool-Water Juveniles 0.35
Warm-water Adults .03
Warm-water Juveniles .05
On an individual basis, larger fish will use more oxygen than smaller fish. However, since the above numbers are per 100 lbs. of fish, there are many more individuals in a juvenile group at 100 lbs than adult fish. Therefore, the oxygen consumption is higher per group of juveniles than per group of adults.