Translation guide
The animal cuttlefish, often encountered in food contexts. The most common Japanese word is イカ, which covers both squid and cuttlefish. For precision, コウイカ is used.
Referring to cuttlefish as a sea creature or as food, where the general term for squid/cuttlefish is used.
The everyday word for squid and cuttlefish. In most contexts, Japanese does not distinguish between squid and cuttlefish, so イカ is the natural choice unless scientific precision is needed.
Have you ever eaten cuttlefish?
I saw a big cuttlefish at the aquarium.
The specific word for cuttlefish, used in scientific or culinary contexts where distinction from squid is important.
Cuttlefish have a cuttlebone.
When you need to emphasize that it is a cuttlefish and not a squid, for example in biology or detailed cooking.
In everyday Japanese, イカ is the umbrella term for squid and cuttlefish. コウイカ specifically means cuttlefish and is used when the distinction is necessary, such as in biology or when the cuttlebone is relevant.
イカ includes spear squid, cuttlefish, and others.
Study the ecology of cuttlefish.