Clownfish ending up filter colum!

[TMH27]

Hi all,
I've got the fluval evo 13.5 and I had a issue with algea in what I think are dead spots of flow.

Decided to upgrade the return pump to the lecce 1.0 algea is all cleared up, and coral are flourishing with new added flow.
But I keep finding my 2 very small clown fish in the middle filter colum?
Had anyone ever had this?
Is it just that they are small enough to get sucked into filter?

All advice and opinions appreciated.
(Based In uk)

 

[fishguy242]

can you put screen or fishnet netting over intake ?