Black Sand Diving, Tulamben and Amed, Bali, Indonesia

Battle of the Black Sands, An epic battle on a miniature scale.

Black Sand Diving in Tulamben and Amed, Bali, Indonesia is known around the world. Many tourists flock there everyday to party, take a dip off its tropical beaches and enjoy a relaxed holiday with lots of cheap shopping. It is also a mecca for local and international divers to visit and draws in crowds from all over the world to dive its beautiful clear waters.
The truth, unknown to many who enter its conspicuous waters, which hide a dark and deadly secret below its deceitful surface.

Every year on the black sands off a select few of Indonesia’s beaches tropical beaches, a massive slaughter takes place.

Stylocheilus striatus, Sea Hare on Indonesia's black sandWith tiny eye spots sensitive to light and dark, and a pair of rhinophores on their head, the Stylocheilus striatus, Sea Hare¸ with its distinctive bright blue spots gather in massive numbers to breed. As simultaneous hermaphrodites they are both male and female at the same time. Mating, isn’t a monogamous affair. Three or more line up at the same time and each sea hare is female to the one

Mating triad of the Gymnodoris ceylonica nudibranch

behind, male to the one in front, each breeding with two other sea hares at the same time.
Sea hares are herbivorous animals and feed on algae and seagrass with flourish in the warm waters off Indonesia. With food and other things on their minds… they find themselves vulnerable to predation.The Stylocheilus striatus, Sea Hare with its elongated rhinophores and eye spots clearly visible

A large species of nudibranch, the Gymnodoris ceylonica, found in the same seagrass beds as the sea hare, is a true carnivore and feeds almost exclusively on Stylocheilus striatus. Following the slim sent trails left behind by the sea hare the nudibranch tracks down its prey.

Finding the bounty of amorous sea hares, the nudibranchs do not hold back in the feeding frenzy!

The ink sack clearly visible has not ditured this nudibranch from making a meal of the sea hare

Launching into a feast they gauge themselves on the little sea hare. However the sea hair is not as defenceless as you may think….. it has a trick up its


Like other molluscs it has a secret weapon. A toxic ink sack which it will use to confuse and put a distasteful taste in the predator’s mouth.

The ink is purple in colour and can be summoned to deter an attack.

This technique is successful in some cases but, unfortunately for many it just isn’t enough to deter the slaughter. For the unfortunate ones the worst is yet to come as the large nudibranch swallows its prey alive and whole.

Egg laying Gymnodoris ceylonica nudibranch after the feastAfter such a feast a few of the lucky nudibranchs need a good clean from the messy meals they have just consumed and that where a little commensal Emperor shrimp, Periclimenes imperator, steps in. The shrimp lives on the surface of the nudibranch, offering him a safe haven from predators like snapper that would make a quick snack out of the tiny shrimp and providing some extra food from the substrate that has been disturbed by the large nudibranch. As for the nudi, the shrimp consumes any parasites on its skin and cleans up after him.

 This emperor shrimp cleans up the nudibranch after the feast on the sea hares
If you would like to see this amazing event it occurs during October on the island of Bali.

Tulamben Wreck Divers ( offer great dive and accommodation packages to dive this amazing site.

Whilst your there don’t miss out on diving the amazing USAT Liberty Wreck dive just across the road from your accommodation. From schools of bumphead parrot fish to the tiny pygmy sea horse it truly does not disappoint. I was lucky enough to encounter a rare mola mola on my visit to the wreck.


To book your trip email on or give them a call +6236323400


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