Kaat

I have made a few quilts but never anything but squares. I now see I should have watched a few videos before attempting triangles. The problem now is I want to hand quilt it but the colors are too different. I was planning on using off white quilting thread and stitching in the ditch. However, that was before I decided to put bright blue water next to brown boats. I have read that invisible thread should not be used for hand quilting. Any advice on how I should quilt this? BTW machine quilting is not an option.
I am kind of embarrased about the close up, but really need advice on how to quilt it.