Fish do like to hang around overhangs and tree roots. In my garden pond they
think they are hidden under lily pads (with their tails sticking out).

Your pond is much larger than the normal backyard garden pond. You can ask on
misc.rural. And we do have some large pond owners who post from time to time.

Your concern about the pump is warranted but a lot of stuff is going into that
pond on a regular basis, tree leaves, fish waste, insect bodies, blown in dirt
and sand, general debris from wind storms. If you have the right kind of pump
it will be okay. Eventually all pumps wear out. Really depends on the quality
of the pump.

Another concern is the kind and amount of fish which were put in the pond. They
will breed. This is where mother nature can help out by sending predators to
your pond. Depending on where you live snapping turtles will show up,
bullfrogs, herons, kingfishers, snakes, raccoons, mink - there are a host of
hungry critters out there, including little kids with fishing poles, and they
will help keep the fish population within reasonable limits.

good luck!

kathy