We have a pond at school. It was a pre-made shape, partially donated by a
local nursery. It is very small, kidney shaped, about 2-4 feet and 6 feet
long. Most of it is only 12 inches deep, with a deeper 18 inch part.
We are in Massachusetts. The pond is in an enclosed courtyard. In the winter
it does get a film, sometimes a few inches of ice. We have a heater for those
days for a hole for air. We bury the irises in the ground for the winter,
but the waterlilies, in the deepest part came back this year. We don't feed
the fish in the winter, though we do, a little in the summer to keep them
friendly for the kids. The first grade tadpoles which the fish don't eat, do
become frogs during the summer, but I don't see any sign of them in the
spring, after the winter.
We don't have a filter, though we do have a water pump. The fish take care of
mosquito larvae. My fifth graders do a partial water change a couple of
times a year and scrap the algae. They also pick out leaves and mulberries
that fall in. Our fish have stayed healthy and grown, much to the surprise of