hydor koralia question

I have two of these running in the tank. I noticed how open the front of them are.
Has anyone had a problem with fish swimming inside of them and getting chopped up by the propeller?!!!

 

They include a fish guard.

 

+1

an Anemone on the other hand is in trouble.

 

I got mine used. They have four 2" openings in the front. Is that where they get a guard?

 

Mine look like this.
http://www.livingreefs.com/attachments/4315d1259937937-hydor-koralia-2-circulation-pump-powerhead-ul-600-gph-41jhg0bnsol._sl500_aa280_.jpg

 

There's a piece that goes on the front with a fish guard and a flow director.

 

i know a person that runs them just like that in the picture with no problems. yet he does have 4-6 inch fish so they probably wouldnt fit

 

and lettuces nudis, Sea Hares, I even lost a fish (happened 3 time before it finished him off). Even with the fish guard on. Mine got stuck to the sides

 

that fish must have been sick or weak before hand... unless it was a very small fish?

 

I just added 6 Green Chromis so Im worried. What should I do?