A Family of Seven

I’m a family of seven,
Two are bitter and harsh,
Four are twins,
The last is the warmest of all.

What family am I?

The Seven Seas. The first two are bitter and harsh, the north and south ones are the twins, and the Indian Ocean is the warmest of the bunch.

Arctic Ocean

Antarctic Ocean

North Atlantic Ocean

South Atlantic Ocean

North Pacific Ocean

South Pacific Ocean

Indian Ocean

The Seven Seas. The first two are bitter and harsh, the north and south ones are the twins, and the Indian Ocean is the warmest of the bunch.