Is it a big clam?

I bought a little one attached to a rock I didn't like. It was so wedged on there I couldn't even see the foot or byssal threads. I tilted it at a slight angle for a few days, forcing the clam to shift a bit so the bottom end was more exposed. Then I just squirted water at it occasionally. Regular old tank water, just lightly enough to bother it. Leaving it tilted a bit, it was easier on the clam to rest right side up on the sand bed than hang on to a rock sideways. It took a few days and it was just a tiny clam. On a big clam the angle might stress it too much.