Has anyone come across a bottom drain that is fish-proof for anything
over a couple of inches in length?

I just found two fish in my bottom drain filter basket tonight. One is
alive and in my fish hospital. The other was basically shredded. I
think it actually cushioned the other enough that it survived, but
yikes. These were maybe 5"-6" long fish, so not huge, but not
something that should end up in the filter basket.

I've fought with this drain cover for the past two years trying to
make the gap between the pond bottom and the cover narrow enough that
the fish can't enter it. Clearly, there's still a problem.

I have skimmers, so I don't need a cover with a wide opening for large
debris, just small debris and water circulation. Any ideas?

Thanks,

Dave