[turkleton]

Yes, I'm afraid an adequate sand bed is a must for this type of fish. Since they burrow into the sand bed to hide when frightened and to sleep, the lack of a sand bed results in long term stress which can affect their health in a multitude of ways. That being said I have spoken to people who have had success keeping these wrasses in a bare bottom tank, so long as there is a large Tupperware container filled with sand in the tank along with them. I don't know the long term effectiveness of this solution as the fish reaches an adult size, but for the short term it seems to work fine. I should also mention that with the Tupperware method it becomes quite a challenge to keep any more than one of this species since the sand becomes a prized piece of real estate and they apparently become fairly territorial.