PATTAYA, Thailand – In Thailand, squid is commonly referred to as a “fish” in everyday language, a habit many people grow up with without ever questioning its biological classification. You will hear it in markets, restaurants, and daily conversation. However, the surprising truth is that squid is not a fish at all. Scientists classify squid much closer to shellfish and other mollusks than to the fish commonly found on our dinner plates. So why has this name remained in everyday use for so long?
What Is a Squid Really?
Squid belongs to a group of invertebrates known as cephalopods, which also includes octopuses, cuttlefish, and nautiluses. Unlike fish, cephalopods have no backbone and possess a completely different body structure from vertebrate animals. These marine creatures are known for their tentacles, advanced nervous systems, highly developed eyes, and their ability to move by expelling jets of water. Scientists consider them among the most intelligent invertebrates in the animal kingdom. Biologically, squid belongs to the phylum Mollusca, the same major group that includes clams, oysters, mussels, and snails.
Why Is It Called a Fish?
The answer lies more in language and tradition than in science. Long before modern biological classification existed, people grouped aquatic animals together based on where they lived rather than how they evolved. If an animal lived in the sea or river and could be eaten, it was often called a type of fish. This is why terms like “squid fish” became widely used in Thailand and remained part of everyday speech even after science showed that squid belongs to a completely different animal group.
Squid Isn’t the Only One
Squid is not the only example of this naming confusion. Dolphins and whales live in the ocean and swim like fish, but they are mammals that breathe air and nurse their young. Starfish are also not fish at all, but belong to a separate group of marine animals called echinoderms.
More Related to Shellfish Than Fish
Although the word “fish” is still used in everyday Thai language, squid is biologically much closer to shellfish than to tuna, snapper, or other true fish species. So the next time you order grilled squid or calamari, remember: despite its name, squid is not a fish at all. It is a highly evolved mollusk, and its common name is a reminder of how humans once classified nature long before modern science provided clearer definitions.
