You can make a nice screen for pretty cheap. What I do is go to lowes and buy one of the window screen frames they sell. They are like 8' long. I buy a bag of .140" screen spline and a 4 pack of screen corner pieces. Just cut the frame into pieces and connect them all to the corners. A hacksaw comes in handy. Then you put the screen over the frame and push in the spline to hold it in, you can buy a cheap spline tool but I just use a screwdriver. Also, I forget which size corners to buy... It depends on the tank size really, but don't forget to match it with the same size frame. When you have everything together, it's not hard to figure out. You cam make a pretty small screen section using this.