To me, keeping a mandarin is more dependent on size of system (or amount of live rock, depending on how you look at it, but these two variables are roughly linearly related), and whether the fish adapts to being fed, and how much competition there is.

The population of pods surely is larger with a sandy or rubble substrate but I think relying on the tank to self-sufficiently feed the mandarin is likely doomed, since pod populations tend to come and go anyhow.

One trick you can try, get some coral rubble pieces and pile them up. This technique is called "pod piles" (if you want to do a search), but the basic idea is that it gives the pods a spot to hang out and theoretically escape predation therefore increasing their numbers. A sort of in-tank refugium, so to speak.

Mine was near 4 yrs. old when I switched to a barebottom. Despite him eating mysis & bloodworms, he did start loosing weight. Had to move him to a friends pod loaded tank to fatten up.

I agree with Tony. If one has a large amount of rock, which seems not to go with the barebottom idea and things like rubble piles or something, which also collect detritus, then the pods would have someplace to hide. Or a large enough tank.

Interesting, thanks guys. I would really like to have a mandarin, but I obviously need to make sure I am able to keep enough pods to keep one healthy. I have read various ways, so once I am up and running, I will give it a shot.

Thanks again!