Largest Sharks Chart I Have 3 Bala Sharks, The Largest One Looks Like Its Mouth Is Stuck Open...there Is Nothing Lodged In It.?

I have 3 bala sharks, the largest one looks like its mouth is stuck open...there is nothing lodged in it.? - largest sharks chart

The mouth of the ball more firmly shark seems to open, there is nothing lodged in him, but he moves very slowly. Is this normal? It is a school of 3 now, and none of the others have a problem.