I've never tried to line the sides of a pond so can't be sure of anything. However, I don't see what would make it adhere and overcome gravity. Maybe if you built it with a really gradual slope, it could work. If it were me, and it's not, I would either downsize back to good clay or possibly find another site.

It's not about the fish. It's about the pond. Take care of the pond and the fish will be fine. PB subscriber since before it was in color.

Without a sense of urgency, Nothing ever gets done.

Boy, if I say "sic em", you'd better look for something to bite. Sam Shelley Rancher and Farmer Muleshoe Texas 1892-1985 RIP Grandpa