I was given a few water lettuce about 2 months ago threw them in a floating planter i had made a while ago. Out grew it with in a couple of weeks. Made a few more floating planters to accommodate the water lettuce for now. How much is too much in regards to plants especially the water lettuce. Ive only ever had the iris, water mint and water cress. Pond looks a bit messy but the fish spawned for the first time this year and the lettuce is sheltering them. Other than that I think the fish are enjoying it for shade.