YOU SAID:

the fish got out and swam to the ocean

INTO JAPANESE

魚は海に出て泳ぎました

BACK INTO ENGLISH

the fish went out to swim

INTO JAPANESE

魚は泳ぎに出かけた

BACK INTO ENGLISH

the fish went swimming

INTO JAPANESE

魚が泳ぎだした

BACK INTO ENGLISH

the fish swam

INTO JAPANESE

魚が泳いだ

BACK INTO ENGLISH

the fish swam