"rc" wrote in message
ups.com...
What about snails or the catfish that are sold as algae eaters ?

As far as I know, there are no species of temperate catfish that would do
the job of cleaning the bottom of a pond. This is the same problem that
Marine aquarium enthusiasts experience, since the only salt water algae
eaters besides snails are usually not suitable for a marine aquarium
because of size or other factors. However, if you live in the tropics, you
can always add a plecostomas or two. :-) (oh, if someone would only
create such a critter for use in a temperate environment). Snails are good
as scavangers, but considering the surface area of most ponds, you would
need a whole lot of snails. Unfortunately for this purpose, they also make
a tasty treat for most pond fish. My pond has snails, but they are very
small, and nearly of of them are hidden in the rocks of the waterfall where
the fish cannot get to them. And at any rate, bottom feeders produce their
own waste so while they are eating the algae, they are also adding to the
nutrient load, which will feed the next generation algae bloom.