It looks like possums probably aren't a pond pest.
Here is what I found out about their diet -
The possum's diet consists of small animals such as baby birds and rodents,
and other dead animals. It is mainly a scavenger, and does not hunt often.
Opossums are omnivorous and consume an amazing variety of plant and animal
foods. Invertebrates, such as insects, slugs, snails, and worms, can comprise a
large part of their diet, and they're not above scavenging carrion.
Diet: Fruits, vegetables, nuts, meat, eggs, insects, carrion

And I agree with ajames, the scent of water is most likely how raccoons find
your pond. Raccoons have been known to raid container ponds several stories up
in apartment buildings.


k30a
and the watergardening labradors
http://www.geocities.com/watergarden...dors/home.html