YOU SAID:
fish swim upstream in trees
INTO JAPANESE
魚は木の上を遡上する
BACK INTO ENGLISH
fish swim up trees
INTO JAPANESE
魚が木の上を泳ぐ
BACK INTO ENGLISH
fish swim on the tree
INTO JAPANESE
魚が木の上を泳ぐ
BACK INTO ENGLISH
fish swim on the tree
Okay, I get it, you like Translation Party.