Would a dwarf lion hide a lot during the day, I don't want to buy it and never see itAbsolutely not, a lionfish would outgrow that tank very quickly, with fins sticking out of the water and such. You should consider a dwarf lionfish instead. Lionfish need 75-120g+ tanks.
EDIT: Just realized that you said Dwarf Fuzzy Lionfish. Yes, a single dwarf fuzzy will go well in that tank. My bad. Heh Good luck!
What would be good tank mates in that size tank? I know the lion fish will eat anything that will fit in its mouth but I'm not sure on what tank mates to getDwarf lionfish will initially hide during the day, but after a while of being accustomed to the tank, the lionfish will eventually be in open view for most of the day light hours.
Iv been looking at valentinnI puffer, would a pair of large clown fish be too small and aint seahorses quite hard to look after?I think some dwarf seahorses might work, maybe something else.... You have a lot of options. Just be sure that neither fish is big enough to eat each other.