Goldfish, specifically, are notorious for eating pond plants down to the nub and also for uprooting them, koi, also being of the carp family, are excellent at this too. With this in mind, the easiest option to ensure your aquascape survives their hunger is to just make your wetland filter plants the main plants in your aquascape (where the fish cannot reach them). 

It is also important to have your pond plants in place and established way before adding your fish, especially if your pond does not have a pond pump or pond filter, as the plants need to be established in order to provide an adequate amount of oxygen to the fish and to also remove toxins from the water as the fish release their waste products. 

This is another reason why wetland filtering plants are important, as they do not rely on the amount of carbon dioxide released by the fish in order to grow at their top speed.  

Far worse than any fish you could possibly stock your pond with, ducks have the ability to eat and destroy your pond plants in AND out of your pond. They're about 3000 times worse than goldfish (a technical number) when it comes to destroying plants, in general. So with this in mind, in order to make sure your aquascaping survives, it is necessary to choose plants that grow to be be bigger than your ducks and that grow fast. 

You also want to make sure that you have a lot of plants. The more plants, the merrier, actually, because I actually designed my duck pond aquascape in order to create a sustainable source of food for my ducks.

Although ducks are greedy, little feathered monsters, they only tend to completely destroy plants when they don't have other things to eat, so it is important to not only provide way more plants for them to graze on, which gives the plants a chance to regrow, but also to feed them while the plants become big enough to provide more food for your ducks. 

It is important to observe how the plants are doing once you add your pet fish or ducks to your aquascaped pond to see what survives, what thrives, and what dies. Anything that dies or disappears, doesn't mean that that choice in plant was a failure, it could mean that your ducks or fish found that plant especially delicious, in which case, if you planted far more of them and kept them protected with a plant cage until the plants could get very established and large, you will have succeeded in finding an excellent, sustainable food source for your ducks and fish. 

Although ducks only get to a certain adult size after a couple months of growth, fish take much longer to reach their largest sizes and need to be fed on a regular basis in order to grow quickly. You can reduce the amount of feed you have to give the fish by hand by finding an edible plant that they love and that filters the water as an aquatic plant or as part of the wetland aquascape filter.

I have also found that as I make adjustments in my aquascape plants to accomadate the vigorous appetites of my flock of ducks that I discover super cool plants that produce food for them and for people. One of my favorite aquascape wetland filter plants that I am growing pond-side, is the banana plant. After discovering just how much the ducks loved eating the banana leaves and trunks, after I happened to be driving by a place where someone was cutting back their banana plants for the winter and shoved them into the backseat of my car and into the trunk to drag home for the ducks, I added 30 banana plants to the food forest this spring and am currently waiting to see if the banana plants from last year decided to overwinter or not.