Can I access std::cout when using <fstream>?

The <fstream> header inherits the <iostream> header. So, in theory, I should be able to access the std::cout object to stream my output to the command line. My question is, how do I access it without including the <iostream> header again and then using the using namespace std statement?

#include <iostream>

using namespace std;

int main() {
    cout << "Hello, World!" << endl;
    return 0;
}

What I want to achieve:

#include <fstream>

using namespace SOMETHING HERE TO BRING COUT TO THE WORKSPACE;

int main() {
    cout << "Hello, World!" << endl;
    return 0;
}

Is having <iostream> redundant after having <fstream>? Does it have any effect on the final build, or will the compiler optimize this?