Overflow Cup Issue

[Gauge]

My tank has two very small fish in it, and I have a sump w/ an overflow cup on it. Twice now my juvenile tomato clown has fallen into the overflow through the slits. I am uploading a picture to show how wide the slits in the overflow are.

I'm looking for some way to block this, but I don't want to put a sponge over it. I don't want anything on there that will filter junk out. I just want it to keep fish from falling in. Something like mosquito netting or whatever.

 

[fishfreek]

Well the problem with bocking the slits is that it can/will impeed the water flow rate thru them. TO much impedence and your tank will overfill.

If you go to your home improvment store and pick up something they call "egg crate". This comes in like 2x3' sheets and is white plastic 1" squares that they use to cover florecent fixtures. Cut the eggcrate for the front and sides of the overflow box.

Once your fish get larger or used to the overflow you wont have this problem.