Odd behavior for hippo tang

[Fishmas]

I have a hippo tang that has been acting rather odd of late. Fish appears to be healthy and has up until last couple days been swimming out in the open happy as a clam. The last couple days he has been sitting down in a crack in the rocks hardly moving. Sitting in this crack all day. When I feed he comes out and eats then goes back to his spot.

Is he ill. Is this normal yet odd behavior.

Wonder if I should quarantine

[SoloChromis]

Hippos are odd balls for sure. Very quirky fish with lots of strange habits IME. I wouldn't be too worried, I've known plenty of hippos that seem to be tucked away in a crevice all day long, but then I also know plenty that are extremely bold and even aggressive to other tank mates. Is anyone picking on her?

[ca1ore]

Changing behavior is always something to be worried about. How long have you had the fish? Any new piscine occupants? Agree they're nuts, so it may just be some kind of idiosyncratic behavior. How big is it? Your tank is a bit small so as it grows it may be a reaction to being cramped.