I have a Fluval U2 filter in one of my breeding tanks, I have a trio of young Albino Bristlenoses in there. The problem I find with this filter is that although I have a breeding cave in there the male and one of the females like to go in the gap at the bottom between the filter and the mounting bracket. As you have to pivot the filter forward to dis-mount it for cleaning I am worried that I will trap the fish.