UGH! So, after losing one of my Bala Sharks due to it jumping out the tank and me finding it dead the next day when returning home from work, I rescued one from the pet shop that was pretty dinged and beaten up. All was fine until I notice a HUGE piece of gravel in its mouth!! He would constantly have his mouth stuck open with it lodged in there! I managed to capture him and pull him out the tank and attempted to pull the rock out with a pair of tweezers. I had no luck. The rock went back into his mouth/stomach. I put him back in the tank because he was freaking out, flapping all over the place. Jumped out of my hands and fell several times and I was worried about further harming him. Fast forward to the next day. I didn’t notice the rock all that day until later that evening when he once again had his mouth stuck open with it lodged in there. Again, I tried to capture him to dislodge it but the second I netted him, down the rock went back in his mouth. Today I did not notice it, I just fed him and he ate, all is well. I figure if he was able to get the rock in, he can get it out on his own? Hopefully it’s already gone.