Generally speaking I'm more in the give them a lot of hiding places and oftentimes they'll use them school of thought. Eliminate or reduce places to hide and shy but otherwise healthy fronts will usually get over it ime. They're not a cave dwelling fish in the wild and don't particularly need caves in a tank. Their habitat is often rocky, yes, and they spend time in the vicinity of rocks, but in the open, not hanging out in caves all day. Not that caves or cover can't be useful in certain circumstances, like to give a female a refuge from an aggressive male, but that depends on the temperament of the male, size of tank, number in your group, etc.
It also helps to spend time sitting close to the tank. They're a naturally curious fish, will usually come check you out eventually, and this can help tame them to you. More sociable tankmates will sometimes bring them out more, somewhat like a dither concept. Oddly enough, occasionally food makes a difference. Feed them a pellet they don't like much and I've seen them sulk, compared to feeding them a pellet they like. Sounds weird, but true.
But if you have a good sized group like it sounds, I'd expect having the tank be mostly pretty open would help. That's what I've seen with mine and I've kept them (and bred them) for years. I'll have a few large rocks, but I don't normally create caves as such.
