Just a idea here but, my grandpa put old semi tires from his shop in his pond for his cat fish but the ones close to the banks the BG LOVED!! It made a perfect pre made nest for them and they still use them to this day. Plan on doing it in my pond staggered set of 5 or so and put a sand gravel mix inside of them. Have them in about 2 ft of water. Hope this give you some more ideas. Would hold your material and I'm sure if you go to a tire shop you could get the old ones for free!

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