YOU SAID:
I once had a pet frog
INTO JAPANESE
私はかつてペットのカエルを飼っていた
BACK INTO ENGLISH
I used to have a pet frog.
INTO JAPANESE
私はペットのカエルを飼っています。
BACK INTO ENGLISH
I have a pet frog.
INTO JAPANESE
私はペットのカエルを飼っています。
BACK INTO ENGLISH
I have a pet frog.
That didn't even make that much sense in English.