It looks like bass, perch or Catfish would work better for you, the surface water coming over the dam and going thru the swampy area before reaching your pond it's likely gonna be a lot warmer than the main pond.
This is also probably adding nutrients from the main pond and swamp which is probably aggravating your weed problem.
Having a deeper pond would be ideal but this may not be financially possible for you.
Many of the people here have lots of experience and hopefully they can find the best solution for your pond.

Last edited by adirondack pond; 03/23/10 06:05 PM.