They may just be too big for him to get down in one bite. I think all fish do it, (I have a theory)...(I have alot of theories)..
I think the fish can very quickly decipher if the piece of shrimp or whatever has enough meat on it to make it worthwhile to chew up..If it doesn't they spit it back out, and move to something with more meat.
Here's why I think that. When I put in Mysis, sometimes a shrimp will get bit in half(leaving only the tail), another fish will quickly grab it and spit it back out. However, when the food is almost gone, they'll go back and get the "not so meaty" pieces.
This could also be the derranged ramblings of a lunatic.
