Yeah, it seems there have been mulitple repeat questions this week, all of which received adequate answers the first time.
I agree with Harlequin, even though my book says the bare minimum is 75g, a 100g should be the minimum for these guys. I've seen species up to a foot in 75g tanks, and that's just not enough room. Dwarf lions are okay for 30g and up, but leave the volitans to the 100+.