i have a TSN and i have gravel in the tank... ( i know not good for them... i'm taking it every water change going to tile it once it's all out) but anyways... he always takes rocks on every feeding... he has learned to take food then spit the rocks out... had him in there for almost 9 months now with no problem... he will be fine... like everyone else says he will just spit it out after a while...