Got Crabs?

Ok, so this is a semi-blurry pic of the larger painting I am working on. Trouble is, I'm at that point where I don't know if I'm done or not.

Sometimes I just know. Sometimes I agonize. This is one of those agonizing moments.

I'm quite happy with the crabs, but I'm not sure if the "background" is done or not. On one hand I like having the calmer background contrasting with the business of the marks in the crabs. But I don't know if it looks too much like they're just floating in nothingness.

Ugh.

The worst part is that I like it so far and I don't want to mess it up or overwork it if it is DONE. (Sometimes I don't know when to stop picking.)