I've seen these guys in a local pet store and did a bunch of research when I was trying to figure out if I wanted to keep a pair or go back to bettas. He/she could maybe be a bolivian ram. Very simular just less colorful, larger, and maybe more agressive not sure about that tho). But GBR rams that are young have those stripes. That fish is young, few months, not at adult color, and possibly has some stress stripes. Its recommended to put GBRs in only fully cycled tanks as they can be very sensative.