From what I've heard and observed, the spines on the small bullheads (the ones you see in the "cloud" of fry) are too small to matter.

For the bigger bullheads, the LMB eat them head-first so that the spines stay compressed.

"Only after sorrow's hand has bowed your head will life become truly real to you; then you will acquire the noble spirituality which intensifies the reality of life. I go to an all-powerful God. Beyond that I have no knowledge--no fear--only faith."