In some cases large dogs can be a problem, because they like to get into the water; for example, labs and animals like that. Raccoons, herons, snakes, they all eat fish, so you are going to want to make sure you find a way to keep them away. You keep those things away though by using a product called the scarecrow. You can pick that up pretty much in most agricultural places. We have it at our pond store. Along with scarecrows, there are automated sprinklers that spray a strain of water for three seconds. This is to detect motion around the pond. So, it spooks the animal. It doesn't actually hunt it down and shoot it with water, but it spooks the animal. The animal runs off as soon as that water starts spraying around.
