Q. I plan on digging an 1100-gallon pond in my backyard. Instead of the same old goldfish or koi, I am considering trying to keep a school of green sunfish. Would you recommend this species, and is it difficult to find? Finally, is it a hardy fish and does it have any special needs?
A. A surprising number of pondkeepers are turning their attention away from traditional ornamental pond fish, such as koi and goldfish, to other species. Some have “gone tropical.” Water temperature demands, however, make this pretty tough in all but the warmest climates (Hawaii and Florida come to mind).
Others have turned to native fish species. This is a very wise move because the animals are well adapted to the local climate and water, and therefore the likelihood of success is greater. I have visited backyard ponds with catfish, trout, pickerel and sunfish. Not only are these ponds attractive and interesting, but if that extra guest shows up for dinner — out come the rod and reel! (He’s kidding. Really. — Ed.)
The green sunfish, Lepomis cyanellus, is a native of North America. It is found east of the Rocky Mountains, which, unless the recent earthquake changed things, means it is not native to your state. It may be possible to locate it at fishery hatcheries, but I doubt it. California has very strict regulations about importing non-native fish. I cannot say whether an exotic pet store would be able to acquire some.
Sunfish tend to school near the surface, and many varieties have wonderful color patterns. The local pumpkinseed (Lepomis gibbosus) is really a very attractive fish. I am sure they would make an interesting pond fish. They are fairly peaceful except during breeding season — maintaining a small school would not be difficult at all.
The green sunfish would do quite well in your region. It prefers water temperatures around 68 degrees Fahrenheit and can tolerate temperatures in the low 50-degree-Fahrenheit range, but not much lower. The preferred pH is in the 7.0 to 7.6 range, with medium hardness. They grow to about 8 inches in length and will readily take flakes, pellets and, of course, live foods.
Strong aeration and a moderate current (water flow) will keep these fish healthy. The pond should have a gravel floor about 6 inches deep because sunfish dig nests in the pond bottom. They will clear an area about a foot in diameter into which the eggs are deposited. Spawning is induced by a cool winter (50 degrees Fahrenheit) rest period.