Most ponds are built by fishing enthusiasts. It is always the first question I get, “What kind of fish can I have?” Because a pond fishery is so much more than fish and water, this is a difficult question as most ponds are little more. A fishery needs a balanced ecology to sustain fish. Without it, the fish will become sick.
Both warm water and cold water fish can be housed in a pond if the habitat is correct. I recommend rainbow trout as the primary species. The reason is they are the easiest to manage. Warm water fish such as bass, crappie and blue gill require population management with constant care (they over reproduce). As the population increases, the size of the fish are repressed by pheromones. Because in most situations rainbow will survive less than four years, you must stock every year. As a recreational pond owner, you are not a fish raiser but a fish catcher and eater. You must rely on your habitat to feed the fish because fish feed is essentially fertilizer growing copious amounts of weeds and algae. The rule of thumb for stocking is a rainbow will eat any fish half its size; therefore, stock with at least 10” fish hoping for a 20” fish… Oh, chills up my spine and a wrecked outfit: how wonderful!
Because West Nile Virus and Malaria are moving, the common mosquito fish, Gambusisa (Gambusia punctata), will eat insect larvae that transmit these diseases. Only a few fish are necessary as they seem to be born pregnant. They do not overpopulate and at two inches are known as the topminnow predator. Gambusisa thrive in temperate climates. Some fisheries departments regulate their transplant; seek advice.
Fish are absolutely required for a pond. They are a top predator in the benthic. However, a fishery must be approached with great caution. The biggest problem is overstocking. Champion fly fisherman practice with as few as ten fish. Much sport can be yours by not over-extending your ecology achieving a balance.
Glug, a bit of Buddhism: there is a way to have a pond that requires some fish, not too many; some plants, only certain ones; crayfish; a turtle; some birds; a log; and a chair. I will use the chair and the “middle way”.
PonDoc from the pond