YOU SAID:

fish can tuna but a tuna is fish

INTO JAPANESE

魚はマグロができるが、マグロは魚である

BACK INTO ENGLISH

Fish can make tuna, but tuna is fish.

INTO JAPANESE

魚はマグロを作ることができますが、マグロは魚です。

BACK INTO ENGLISH

Fish can make tuna, but tuna is fish.