Looking for advice
I just joined the suite in hopes I can get some pointers. I have discovered 3 small concrete ponds in my backyard. For th past 5 years I thought it was rock until I stepped off in one while mowing the other day. I dont know the first thing about ponds and would like to get them set up. What should I do for filtration and plant life. What fish would be best. I am not sure of the exact size because I do not know the size because I have never measured a pond. A neighbor said the previous owner used them year round for golsfish and koi.