Nocturnal, are they? I've seen them quite often during day....in europe....(perhaps a different subspecies), but also in Vancouver. Anyway...you did well making a photograph of this one...but the steep angle and OOF vegetation isn't really working here. I like the diagonal line that the muskrat makes through the frame...but it would have been nice if it would have had a bit more space to swim into.
I like the vegetation on the muskrat. Not crazy about the OOF grasses on the lower right. The downward angle is different and doesn't work often but with all the vegetation on the water this may have worked.with a looser crop. Other suggestions above are also quite valid..