Translation guide
The small marine fish with a horse-like head. In Japanese, the most common word is タツノオトシゴ, but there are also other names and a mythological creature.
タツノオトシゴ
seahorse (animal)
Referring to the small marine fish of the genus Hippocampus.
The standard Japanese word for seahorse. Literally 'dragon's illegitimate child'. Used in everyday conversation, biology, and aquariums.
水族館でタツノオトシゴを見ました。
I saw a seahorse at the aquarium.
Literally 'sea horse'. Used in scientific or formal contexts, but less common in everyday speech. Can also refer to the hippocampus in the brain.
海馬は魚類に分類されます。
Seahorses are classified as fish.
Literally 'sea horse'. A less common alternative, sometimes used in children's books or older texts.
ウミウマという名前の魚がいます。
There is a fish called 'umiuma'.
Referring to the mythical creature with the head of a dragon and body of a horse, often associated with the sea.
A mythical creature from East Asian folklore, a dragon-horse. Not a biological seahorse. Used in fantasy or historical contexts.
伝説の竜馬が海から現れた。
The legendary dragon-horse emerged from the sea.
The word 海馬 (かいば) can also mean 'hippocampus' (part of the brain). In most everyday contexts, use タツノオトシゴ for the animal to avoid confusion.