In article , Lynda Thornton
writes

Or if you really dont want to do that how about a solar powered pump
http://www.nclsolar.com/p_gard.htm (£85 though)

Unfortunately a lot of things called pumps, including this one, are
actually fountains, rather than submerged pumps which is what I was
thinking of.

A fountain, adjusted to a mere trickle, would do a good job of
oxygenating. And wouldn't upset your water lily.

--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm