I am new to all of this. I love fish, wanted to go to school for marine biology then i picked up my first retic. But i want to learn more about fish keeping. I have an old 75 gallon tank i picked up from my old job. I think its an over flow at the top? its got 3 plumbing pipes sticking out of the top where that box is. i can post pictures in a little bit. I have some gold fish but what would be other fish that i can put in it? i have never done a salt water tank is this too much to start out with? and what about filtration? can i build one?