Hi William,
You have the correct information now, bringing plants of any kind without inspection across the US/ Canada border is a no-no
in the eyes of Canada Customs - you'll probably have to stick to Canadian sources. I'm a Canadian prairie ponder, relatively new to all of this like yourself, this being only my second season of ponding. My pond is also about 400 -500 gallons, about 2' deep fed from a 20' long stream and bio filter. I think you'll be amazed at how few plants will give the surface coverage that will inhibit algae growth particularily in a shallow pond like yours. The water temperature will be fairly warm which will encourage plants like lilies to grow rapidly. Last year I started off with 2 hardy lilies and 4 or 5 water lettuce plants from a local nursery. Probably a total investment of $60 to $70. The lilies are expensive here ...starting at $25 and up in price depending on the type. When purchased they didn't look like much, coming in pots about 4" square with only a few leaves. I repotted them into larger mesh baskets and with a month had plants that easily covered 1/2 the surface area of the pond. This was after a late start in early July so I missed almost half of the growing season! The water lettuce will spread like wild fire also and may need the ocassional thinning out. The lilies can be stored inside for the winter along with some water lettuce ....both wintered very well in the basement with the gold fish and will be back in the pond shortly once pond cleanup is done and the water temps are on the rise.
No fear of not seeing your fish either .....once they figure out that food may be the way when people are about they will scooting back & forth at the surface. I found that mine were less timid and stayed visible more with the plant coverage probably because they could duck to nearby shelter if necessary as opposed to staying in deeper water.
...Garry
