I am not a fish but look like a large fish and live in the sea.I am a warm-blood mammal.What is this?

I am not a fish but look like a large fish and live in the sea.I am a warm-blood mammal.What is this?
I am not a fish but look like a large fish and live in the sea.I am a warm-blood mammal.
What is this?

I am not a fish but look like a large fish and live in the sea.I am a warm-blood mammal.What is this?
译：我不是鱼类,但看起来像条大鱼,住在海中.我是一种暖血的哺乳动物.
It's a whale.（鲸）.