If you still like the island idea, I would look into floating ones. They take up no depth, and can still be a nesting area for wildlife. There are a couple of threads about making your own, and there are a couple of companies that make one. The great thing about the islands is that they allow fish to use them for cover, and they also help filter your pond naturally. You also can make the depth of your pond as deep as you need for your other goals.

I will be adding one to my 1/2 acre pond this summer.

Islands are tough in small ponds because the space they take up underwater is huge compared to what they do on the surface. Also, they tend to collapse and become submerged islands if not handled carefully.

Brian
Retired Coach

Just another day in paradise!