Be it carp, turtles or simple loss of soil due to wind and water currents, the new plants need to be protected.

Ken's suggestion is very good advise for protection from loss of soil and possible digging by the carp or turtles. But to ensure the fish and the reptiles do not feed on your new plants I would suggest a cage of galvanized wire simularly used on tomato plants. Make sure your openings are smaller than the fish or turtles. The orange plastic netting found in Hardware stores works well too.

The plants will be able to grow their roots in the pot and the actual leaf and tuber will grow around the net or fence material and make it to the surface.