Thanks a lot for the response. After your advice I think I will remove the sand. Please clarify what can be wrong? When I say "asking for food" I don’t mean he really says it!!!! I just mean that the turtle is going near a specific corner of the tank in a vertical position giving a sign that he requires food. Actually if a drop some food he eats! Is it strange? Please let me know since your message put me in worries (or the "ask" was the strange thing!). What do you really mean that something IS VERY WRONG?