blocking not covering overflows

[mvallee]

I have two flasher wrasses and one of them keeps ending up in my overflow, I have glass tops on my 180G and there are two overflows and he has made his way into both. There is maybe a 1/4" gap from the top of the overflow to the glass and I am afraid if I just cover it he will end up on whatever I use to cover it.
I was thinking of trimming one of those pool noodle floats to seal the gap but afraid it will deteriorate and pollute the water, any suggestion? I am getting tired of pulling the piping out of my overflows to catch the little bugger.

 

[Marshall O]

I covered my overflows with acrylic. To date, any that have landed on it have quickly flung themselves off. I have 11 Wrasses, and they are quite jumpy