There's an interesting article on the Nopoli rock-climbing goby in Hawaii that has both modified fused pelvic fins and mouthparts that function as suckers. They also have a very different feeding process from close relatives. The story is at:
http://www.msnbc.msn...cience-science/

I have seen those on Kawai. The habitat to me seems to require they use the ability a lot just getting from pool to pool which maybe only a few feet apart. I wonder how important habit is when it some to getting food just above the water line? That appeared to be where a very large part of attached vegetation was in and around streams.

I love those gobies.. One of my "dream" fish.

Very cool fish! The sirajo goby (Sicydium plumieri) is the Caribbean relative mentioned and a little easier to get to then the HI species. Largest adults live and spawn in the headwaters of very steep rivers. The larvae hatch, drift downstream, and out to sea. They migrate back up freshwater streams when they are still relatively small, then appear to work their way back upstream as their larger size allows them to traverse larger obstacles/faster flows. This species also has fused pelvic fins and eats algae.

When I was a younger lad, I did a stint doing surveys for them on the island of Dominica in the early 1990s. Indeed very neat fish. I found a pair in a tiny pool the size of average kitchen bowl that was 15 ft+ off the ground on a vertical cliff along the stream that had a trickle of water coming down its surface. The snorkeling NANFANs would appreciate this story. The streams had a couple varieties of shrimp, possibly atyid shrimp (can't remember). One species was a filter feeder, the other had pinchers. Although not very intimidating pinchers, the latter were very aggressive and delivered a decent pinch. They made the goby snorkeling surveys (just swim trunks and sandals) interesting as they did not occur at high densities but would actively seek you out and latch on. I wish I had a modern U/W point and shoot back then....I had one of the 35mm yellow U/W Olympus cameras that left you carrying film back wondering what you had. I was always disappointed when film was developed...

I dunno, this is a look into how the sausage is made. Herps or fish, lots of people here are curious how the meat grinder deals with new species. Sure it's not directly relevant to NA native fishes but it's providing a forum for at least one side at the moment.