In Hong Kong, vis always bad(<5m)...wide-angle shoot almost seem impossible..
but the marine life in H.K. still are intresting..
used with a wet wide-angle lens, the nudibranche almost stick on the lens

used with a wet macro lens (epoque)

comments are welcome.
my photo albums.
http://www.fotop.net/joetsm
The second shot is beautiful. Great details. I don't think I've seen this one before.
The first one looks like one that's common around here at Monterey CA:
http://www.metridium.com/monterey/nudibranchs/phidiana.html
It's interesting to see one so similar all the way across the Pacific, and in much warmer waters.
thanks! it's funny can find the similar nudi at the opposite side of the world,
yes, water temperature in H.K. is a lot warmer..