Colon / Bridled Goby

Coryphopterus dicrus / Coryphopterus glaucofraenum

These two gobies are very difficult to distinguish underwater. The Colon Goby has a dark spot at the base of the pectoral fin, and the Bridled Goby has a white line that runs from the mouth to the front of the gill cover. If that area of the fish isn't in sight, it's very hard to tell the difference. Both have translucent bodies, with either darkish spots or band at base of tail, and similar eyes. The Colon Goby has brown spots, the Bridled, White body spots. Which do you think is which in these pictures?