I'm thinking of those tubes/tunnels that hold water and allow the fish to travel between the two tanks. I have two 20 gallons that id like to connect. It doesn't have to be a long connection, just for 2 tanks right next to eachother. So is there a way to do this or is it just a bad idea cause the fish won't go thru it? Every site I look on that sells clear pvc but its super expensive, does anyone know a way to connect 2 tanks together that isn't so expensive?