This is the 6071st most frequent Japanese word.
ウオ
"ウオ" (uo) is a casual or old-fashioned way to say "fish" in Japanese.
The word ウオ (uo) here is used to mean 'fish' in a general sense, as it traditionally represents this meaning in Japanese.
ウオは泳いでいます。
The fish is swimming.
In this sentence, ウオ (uo) functions as a proper noun, being the name of a pet.
彼はウオと呼ばれるペットを飼っています。
He has a pet called 'Uo'.
Here, ウオ (uo) refers to fish in the context of buying it for consumption, showcasing its traditional use in referring to fish.