Honestly, your clown knife can't do those damages. I have clown knife and Azul, and my money will be on 12in Azul over 28in clown knife any day. The suction of 3000+gph thru 2in PVC pipe is another story, though...I didnt at first but do now, as of last night. Giraffe is only 15" long give or tank, the clown was 27-28" or so. The very same marks were on the two bass as well.
Honestly, your clown knife can't do those damages. I have clown knife and Azul, and my money will be on 12in Azul over 28in clown knife any day. The suction of 3000+gph thru 2in PVC pipe is another story, though...
Do you have strainer at the end of your intake pipe? That mark looks kinda big to be clown knife mouth