Overflow Screen ?

My tank has an overflow with teeth with gaps between that the water
flows through (as most do). The gaps are about 1/4" wide, plenty big
enough for (just as examples) two-spot goby, yellow watchman, neon goby,
etc... to fit through. I've had to fish these guys out of my overflow
or sump a couple times now. How does one prevent this? Seems to me
that a mesh screen would clog, which could be ... bad... :-)

Thanks.
Eric
http://www.atreis.com/sal****er1.html