I have a bay front type of =BFpond?

Not really a pond more like a fishing pier docking posts etc. without
plants...I have had my pond without plants with great success....it's
been like that for about 13 years with no diseases or deaths."not
counting baby pump fatalities" ...but it is shaded from the Texas
summers with a large terrace.
..

Maybe my nitrates are non exsistent because there are almost "0" plant
residue and muck in the pond as the terrace eliminates any stuff from
falling in?