YOU SAID:

I am a speckled fish who is thick

INTO JAPANESE

私は斑点の魚は厚い人

BACK INTO ENGLISH

I'm a man spotted fish

INTO JAPANESE

私は魚を発見した男

BACK INTO ENGLISH

I was the guy who discovered the fish

INTO JAPANESE

私は魚を発見した男だった

BACK INTO ENGLISH

I was the guy who discovered the fish