My understanding is that the Costa Ricans are usually more white to grey in the base color with way more blue in the fins, whereas the nics are more gold to yellow base color. I don't think the stocky body shape really becomes noticable until they get to a very large size. With these fish lighting can really affect the way they look in photos so it's hard to say, but I'd guess yours is probably a nicaraguan. Things could change as it grows or it may appear different if we had more photos/angles.