Cuttlefish
Cuttlefish are marine cephalopod molluscs in the order Sepiida, related to squid and octopuses.
Cuttlefish are marine cephalopod molluscs in the order Sepiida, related to squid and octopuses. They are known for their internal cuttlebone, ability to change colour, and short life cycles of about one to two years.
What it is
Cuttlefish are not fish but cephalopod molluscs, with more than 120 living species. They have a soft body, large eyes, eight arms, and two tentacles. Their distinctive internal cuttlebone is a gas-filled shell that helps control buoyancy. They are part of an ancient lineage related to squid, octopuses, and nautiluses.
Where it lives and what it eats
Cuttlefish occur mainly in tropical and temperate marine waters, especially shallow reefs, channels, and seagrass areas. They are active predators, feeding on molluscs and crustaceans such as shrimp and crabs. They use vision, colour change, and camouflage to hunt.
Why it matters
Most cuttlefish species are listed as Least Concern or Data Deficient on the IUCN Red List, though the giant Australian cuttlefish is Near Threatened. They are not native to Canadian freshwater systems, but Canadian readers may encounter them in marine biology, aquarium contexts, or seafood discussions. Their short lifespan and rapid colour-changing abilities make them a subject of behavioural and conservation interest.
In short
- Cuttlefish are cephalopod molluscs, not fish.
- They have an internal cuttlebone for buoyancy control.
- They live in shallow coastal marine waters worldwide.
- Most species have a lifespan of about one to two years.
Cuttlefish are not native to Canadian freshwater systems, but Canadian readers may encounter them in marine biology, aquarium contexts, seafood discussions, or studies of cephalopod behaviour and conservation.
Quick questions
Are cuttlefish fish?
What is a cuttlebone?
What do cuttlefish eat?
Sources
- PBS Nature — https://www.pbs.org/wnet/nature/blog/cuttlefish-fact-sheet/Supports: Taxonomy, number of species, and conservation notes including the giant Australian cuttlefish's Near Threatened status.
- PBS Nature — https://www.pbs.org/wnet/nature/animal-guide-cuttlefish/1161/Supports: General biology, habitat, distribution, diet, lifespan, size, and species count.
- Science Focus — https://www.sciencefocus.com/nature/everything-you-wanted-to-know-about-cuttlefishSupports: Cephalopod classification, cuttlebone, habitat, diet, lifespan, and distribution.
- The Wildlife Trusts — https://www.wildlifetrusts.org/wildlife-explorer/marine/squids-octopuses-and-cuttlefish/common-cuttlefishSupports: Common cuttlefish biology, cuttlebone, behaviour, habitat, lifespan, and UK distribution.