No, there is enough other stuff in the pond for them to eat. They only suck the leafs from the bottom side but don't cut them by biting. They are well educated.
They are fed by about 10% of what they need, only to keep friendship to them. They are mostly self supporters.
A lot of different fishes and other creature are living in the water inclusive a turtle from NC, Trachemys scripta scripta, which suddenly appeared about 10 years ago. I gave it asylum.
But it bites the kois in the tail fin.
I cannot afford a penthouse apartment at 5. Avenue so I moved to the country side.
There is no public water supply so I have to produce drinking water by myself.
In case of fire the fire brigade needs more water to extinguish my 120 years old house than my fountain can deliver so I need a fire-fighting pond in this natural reserve area, the administration told me.
I agreed