YOU SAID:
The duck swam through the murky pond.
INTO JAPANESE
アヒルは濁った池を泳いでいた.
BACK INTO ENGLISH
A duck was swimming in a muddy pond.
INTO JAPANESE
濁った池に鴨が泳いでいた。
BACK INTO ENGLISH
A duck was swimming in a muddy pond.
That didn't even make that much sense in English.