My pond came with the house so I've been learning as I've gone along. Pond is half above and half below ground; sort of like an upside-down volcano shape, about 2500 litres. Just got goldies, couple of rudd and a grass carp in it. Had pond re-lined and re-edged last year with sleepers and stone toppings. Running EA Nexus filter, EA pump and small waterfall pump.