Sadly, we didn’t find snorkelling at Chesterfield to be as good as we’d expected (although perhaps we did not stay long enough or explore far enough to do it justice, but there were still some nice things to see. Here are Alison’s favourite fish, the longnose filefish Oxymonacanthus longirostris which feeds exclusively on coral polyps of the genus Acropora. You can see the ‘file’ on the back of the righthand fish. Note too the black spot on the tail. Lots of reef fish have similar markings which were originally though to be mimicking eyes to fool predators but are now known to be location aids to allow other fish to school more effectively:

 

 

The bluespot butterfly fish, Chaetodon plebius feeds mainly on coral polyps but will clean ectoparasites off other fish; note the black spot:

 

 

The beautiful blackbacked butterflyfish Chaetodon melannotus, also with a tail spot:

 

 

Another of Ali’s favourite fishes we think it’s a South Seas devil Chrysiptera taupou:

 

 

A coral garden - the flimsy looking yellow and red bits are solid limestone rock, secreted by the coral colonies:

 

 

A very smart looking large holothurian (about 75cm):

 

 

A large clam with gorgeous aquamarine flesh; the black dots around the edge of the blue bit are eye spots, extremely simple eyes which serve to spot motion and shadow. They can see just well enough to close their shells when something large approaches:

 

 

A close-up of one of another clam’s siphon – these animals are filter feeders, sucking large quantities of water through their internal filters are straining out the micro-organisms upon which they feed:

 

 

And next up, the real stars of the Chesterfield show – the birds