YOU SAID:
I got to go walk my fish
INTO JAPANESE
魚を散歩しに行かなくちゃ
BACK INTO ENGLISH
I have to go for a walk with the fish
INTO JAPANESE
私は魚と散歩に行かなければなりません
BACK INTO ENGLISH
I have to go for a walk with the fish
You've done this before, haven't you.