six line or a four line.. although I haven't see four lines in a while.. it's like a green six line.. but with four lines.. er, yeah.
anyways... I love my six line.. always on the go, going in and out of caves in the LR... like with any fish the occational one will find interest in the stuff you don't want it to.. maybe get a small one and let it grow into the tank a bit.. my six line has doubled in size over the last year and never bothered any one of my shrimp (blood, coral banded, and peppermint).