stoping raccoons and Herons from eating my fish

Question
Hi; I just bought a house with a nice koi pond. The koi where stolen or eaten as we were in the process of buying the house. I've bought some small fancy gold fish and now some reg cheap gold fish just to have some life in it. Last night I chased a raccoon out of the yard. I've noticed some fish missing. How can I repel raccoons and herons from feasting on my little new pets? I've seen the scarcrow motion sprayers but I've read in this forum they sometimes don't work to well with raccoons. Thanks for any help.

Answer
Hi David,
Thanx for the question.  Critters are hard to keep out of the pond once they find an easy feast.  Cats and dogs help keep these pests away.  That's all I can think of. I've had people write in before about herons and they are just going to hang around if they find an easy meal but cats and dogs do deter wild animals from hanging around.  I hope this helps.
Tom