Daniel -
It looks like H. hassi to me - from the video it looks like the eel is participating in feeding behavior. It's mouth looks to be moving in a feeding posture and that give its head a strange shape in the video.
cheers!
- MDP
Well, the video on the site is of poor quality, but definitely feature two distinct specimen.
First, we've got H. hassi with no doubts. But then I spent five good minutes observing this one (which was part of another colony, approx 80 m. away) and it never looked "normal".
Now, looking at it with a different angle, it may be one individual with the bottom portion of the mouth missing... As this part was sligthly moving I thought it was the whole mouth gaping some food. But it could be that poor fellow, head tilted back trying to feed like the others... a view from face would have probably shown a big hole.
to compare to the normal and mouthless one:


Mike, I think that was a good guess. 
Bty, you can now on tick that we got ornate rays in Australia too ( Milln Reef , Cairns ) ...
Cheers.