Marine Life

Cuttlefish – Marine Life in Thailand

Cuttlefish are one of the most intelligent, interesting and intriguing creatures on the reef is the Cuttlefish. The Cuttlefish is not a fish at all really; it is classed as cephalopod, other members of the Mollusk family are the Octopus, Squid and the elusive Nautilus.

Cuttlefish are found in most of the world’s oceans and seas, although saying that they are not found anywhere around the Americas. We know of 120 species of cuttlefish, and that they vary in size from a small 15 cm to the very largest of the large cuttlefish over a half metre in length (not including tentacles) and can weigh up to ten kilos.

Cuttlefish at Richelieu Rock, Thailand
Cuttle Fish mating

Cuttlefish are carnivorous and love nothing more than munching down on small Crabs, Shrimps, fish; they even have cannibal instincts too. It is a highly evolved predator often referred to as the Chameleon of the sea. Which is due to the way it can dramatically change its skin colour and appearance, in order, not only to defend itself but, also to hunt and confuse its prey.

This amazing little Mollusk changes colour by pigmented chromatophores, through this process the cuttlefish can use the colours, red, blue, yellow black and brown, these colours sit above a layer of reflective skin cells. The pigmented chromatophores have a sack of pigment and a large membrane that is folded when retracted.

They use this skill to fantastic effect, not only to mesmerize prey before consuming it, but to camouflage it against predators too. This wonderful light show that the cuttlefish produces also depends upon its temperament. The creature can change colour at will and does so constantly throughout the day, with different colours being produced depending on its mood at that particular moment.

They have eight arms and two longer tentacles that they use to feel and search for prey. These tentacles have highly efficient suckers which they use to secure prey before consumption. Cuttlefish have a valuable ink sack which inside contains their ink, which they can fire at will to confuse and avoid predators that may have mollusk supper on the mind.

Sepia Eye
Cuttle Fish Eye

Here in Thailand we see these amazing creatures quite frequently, such like in Similan Islands & Surin Islands. In fact it is not uncommon to see two or three of them very close together, especially if it mating time.

It is possible to get very close to them, as they are a very curious, as long as you approach slowly and never from above, you may be able to get within a few metres. If you are really lucky, like I have been on several occasions, you may witness the female laying eggs inside rock crevices.
Prior to the egg laying process by the female, she may have already mated with several other cuttlefish, each time storing the sperm until she is ready to allow the sperm to fertilize her eggs. After mating, the male will guard the female until she lays the eggs, guarding her against any other males in the area that will try and mate with her too.

When this happens it can lead to a fight between the two males, rarely is the fight won by actually scrapping, but usually after the standoff the bigger of the two males will usually posture enough for the smaller one to back down and retreat.

It is all action on the reef and in the cuttlefish world it is no different, you really need to only look them in the eye to see that there really is something going on in there looking back at you. The next time you dive and if you are fortunate to see one of them or maybe more, get as close as you can to it and just observe its action and you too will be amazed at its colorization. They truly are a fascination from the deep.


Cuttlefish Facts

Phylum: Mollusca.
Class: Cephalopod.
Scientific Name: Sepiida.
Found: Worldwide.
Diet: Carnivore.
Average Lifespan: up to 3 years.
Conservation Status: Threatened.
Favourite Food: Shellfish.
Habitat: Coral reefs and deeper waters.
Litter Size: 200.
Predators: Fish, Sharks, Cuttlefish.