I liked the rock around my main pond for bank erosion prevention.
The acidic clay needed lime anyway, so lining the pond with limestone rock took care of that. Probably 75% coverage of the bottom and sides.
I was considering crayfish at the time, and figured the rocks would be good habitat. Crawdads never appeared this year in number because of the drought (so I never found a source of local variety to capture and put in the pond) and once I decided to try the PK shrimp the crayfish idea went away. Figured the crayfish would do away with my PK shrimp. Crawdads are mean, feisty little critters. We've kept them in an aquarium before.
It was a small enough pond it did not take that much rock. I kind of started on the water line around the shore and forgot to quit. The rock is not deep at all. As close as I could come to a single layer of it.
But the reason above all others is because of an observation in my main pond. The limestone rocks seemed to be an ideal substrate for quick algae growth. And every time the water fell and rose again on the rock and a fresh batch of algae grew, snails multiplied by the gazillions. Normally that would not be such a good thing. But since my emphasis for this pond was to raise RES fry from a few adult brood stock into fingerlings, in addition to the FHM's, I knew the RES would have a much better chance of thriving if I had their preferred food in abundance. So it was the snail explosion in the main pond on the rock that induced me to use a lot of it in this small pond. I actually inoculated this pond with algae and snails as it first filled.
