They didnt escape, I know that much. I put them in a flipped over bowl so they couldnt bury and in the morning they were gone. Look at the bottom left of this pic:
I would feed him like this:
1) Sift through the sump to find 5 clams.
2) Put the clams in the FT (Feeding Tube).
3) Shake the FT near him and if he was hungry he would grab the FT and hold it still then stick an arm in and grab the clams.
4) Repeat with 5 clams a time until he was no longer grabbing the FT.
5) Put 5 clams in the bowl for him to eat over night.
I think this process worked well. It was exciting though when I fed him the Periwinkles and he rushed out of his den for them. 8)