Cuttlefish are a common sight on the reefs around Koh Lanta in Thailand and you can get extremely close to them when they are preoccupied with mating.
There are more than 100 named species of cuttlefish and they are found everywhere from the Eastern Atlantic (one of the treats of UK diving) to Australia (though not New Zealand).
These fast growing Sepia pharaonis 111 seem to mate all year round.
The males can be identified by their spotted front arms raised to ward off other potential suitors eager to fertilize the female's eggs. Like rampaging elephants with trunks raised, the males will charge at rivals. The female stays close to the seabed finding suitable places to deposit her eggs.
* Magnus is the photo pro at Scubafish in Koh Lanta. You can see a full portfolio of his work plus a guide to diving in Koh Lanta in the Winter 2017 edition of DIVE.