Bass, water snakes, turtles, herons.
Bluegill should be kept in a large pond they are a sport fish rather than an aquarium fish and they're regarded as good eating too.
Bass and bluegill are nearly always used together to stock farm ponds. The bass eat bluegill to keep the population in check, and bluegills will eat bass eggs, so a balance is kept.
Three types of forest populations that could not survive in a pond ecosystem are monkeys, ants, and birds.
they can be shallow or deep.
It needs to be atleast 2 ft deep if you want to keep the fish in the cold weather however i would suggest going much deeper to be on the safe size, a small pond can have steep sides to dig to about 3 ft and there will be no problems with the fish in cold weather, other than that it is not important how deep the pond is, as long as they can swim freely.
Bluegill fish can be found in freshwater lakes, ponds, and rivers across North America. They prefer shallow waters with plenty of vegetation to provide cover and food sources. Look for Bluegill fish in areas with slow-moving or still water, like near docks, fallen trees, or weed beds.
Goldfish can survive in a pond without a pump, but it is important to ensure that the pond has enough oxygen and is properly maintained to support their health and well-being.
If the pond is not deep, the fish can leave the pond. It is important to take good care of them or they will be tempted to leave.
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The pond water must contain high nitrogen levels.
A pond with sloped sides is necessary to allow for the frogs to get in and out of the pond easily. Using a flexible pond liner so that the pond slopes from shallow to deep is advisable.