solutions for my filter?

[V p1839]

So I have a problem....
I have a Penguin 150 in my 12g tank. I have guppys that are being pulled in the intake spout. There is no speed regulator for this filter either.

Now what I want to know is what can I put over the intake vent to protect my poor fishies.

 

[reefdiver]

U can use a stocking or a pie e of sponge

 

[V p1839]

I'll try a sponge