Im in process of trying to do on larger scale, but a koi and five snapping turtles are making difficult. the ducks themselves will in beginning after setting in eat most aquatic plants, marginal plants, and surfaces plants. i have had great success with irises as water plants, though the ducks do eat flowers and at times seeds from opened ponds. I've heard cattails will work, as know willows and horse/coachwhip plants do. duckweed will be eaten but if in mass poured in dense bed of irises they seemed to populate enough. parrots feather can be planted also among /under dense irises and can endure, but my pickerel weed and water celery couldn't endure well enough from plucking/trimming of ducks to thrive from manure like other plants. eladosa grew well and ate ate, but algea and trampling along with possible over fertilized too early (i heaped handfulls of duck poo on my project after took off at first) and great pond snails and fish devoured, and then stems got mooshy from algea bloom and too much poo. water lillies and lotus did really well, though think water lotus maybe toxic or at least ornamental strain i had. DON'T use "water lettuse", as told its extremely toxic. water hythinth on other hand can create itching mild to major if eaten by and maybe touched by sensitive people, but ducks had no trouble after got used to after week nibblings at (then devoured half as fast as could grow for scovy males). on fish and snails-ramshorn snails were pretty unobtrusive but breed really slow compaired to great pond snails, but great pond snails preferred over ramsohon and trumpet snails as feed, breeding eaisly and much more rapidly for food). mosquito fish are able to grow breed and thrive (tossed out 200 huge breeding females alone at one time this fall to make more room for winter). Everything seemed to feast on them even damsel fly larve ect, and thirteen muscovy ducks. to do this spring id probly make larger than small and med kiddie pool put into ground (great hiding for ducklings but you won't see them most of day and only head of mother occasionally). Ideally you want to go with four feet deep, freeze hardy for most climates, but maybe five to five and half feet so have 12-18nchs of pea gravel to plant in too to anchor plants for first week to month. three feet total with one being pea gravel may work enough to grow and breed rosy/chub minnows in, but need extra foot or so for goldfish to koi (koi need four feet deep water to swim breed and get away from preds decent, supposedly). id say size of largest kiddie pool can get and bury to bottom of rim (drilling small run off holes so don't overflow fish), should do good for half dozen ducks (i had a Scovy mamma appa and dozen ducklings in med-large kiddie pool for two months before was bleh) i had mosquito fish and frogs and still got horde of mosquitos breeding in irises). haven't tried longfin koi sadly yet. as want so can't say on them, but they are faster smaller and way hardier than traditional koi. Only one goldfish per twenty gallons for system sustainability if they are used. No filters used but bucket of pond muck/scum good for jump starting this sydtem letting settle for week full before adding fish ect or ducks back. To control algea and promote good bacteria you can use barley bags (just tight clumps of barley straw), and aquarium grade "activated charcol". The plants in fall all did great and actually were outgrowing the pool and containers (literally growing out of warping and busting), until they all went into bloom, then parents started devouring and after decided down along stalks and stems were delicious too. they had mossy logs ect all over around pen they ate at and perched on and hunted critters through, so maybe why they didn't devour pond playland bad earlier . the pond plants did come back continually just eventually had to rotate and got tired of constant mosquitos and frogs, though scovy fam got to be butterballs until i took out pool to try to seed larger pond with koi n goldfish n panfish. the koi uprooted and messed up any and every small plat tried to plant to spread them out more from large mat clumps they'd become. koi was already here as landlords pet, but one female and four male snappers new, and have to fish them out and cull half a dozen drake scovy (drakes eat and destroy at least three to four times as much as females). My mallard type KC breed are a lot messier though young, and told mallard type ducks are a lot more destructive than muscovy ducks.
