Ever played call-my-bluff? No, not the tv panel game with the much missed Fwank Muir. Try one of the natural history variants like call-my-neotropic-hummingbird-bluff, or call-my-tundra-flora-bluff. You get to falsify names and hide them amongst real species, and this week I've been playing call-my-reef-fishy-bluff.
Orange-spine Unicornfish? Bi-coloured pepperfish? Brokenbar Butterflyfish? Oriental Sweetlips? Powder-blue Surgeonfish? Which is the piscatorial hoax?

Join a week cruising the atolls of the Maldives and like any boat there are usually a few games on board. Share the experience with a cross-section of ages and the sillier the better. Our leader, the marine biologist and foremost authority on Indian Ocean cetaceans, Charles Anderson, had brought his son Robert and two young friends, Freddie and Alexander to witness the astounding marine life on offer: a kaleidoscope of coloured fish danced about the turquoise coral reefs, dolphins in boisterous schools of hundreds jostled for position on the bow wave, and ocean leviathans tried to evade our notice when surfacing from sorties to the deep.

After one memorable snorkel with mantas we returned to the boat and immediately started making model rays complete with gaping mouths and gill slits. (My watercolour paper had just the right amount of flex for the giant wings). In another fun game we cut out simple profiles of surgeon fish and butterfly fish and added some of our own designs - hence the call-my-reef-fish-bluff. Anderson's Rainbow Surgeonfish, Warburton's Moorish Idol, and Rees's I Can’t Believe It’s Not Butterflyfish all made the fishy bluff list. Lots of combinations of dots stripes and fantastic colour – a bit like Fwank's bow ties really.

Many thanks to Chas, Sue and Robert. Go see the Maldives with them at www.whale-and-dolphin.com