That pretty well covers your options lol.. Or cage your fish until they are plenty big enough to fight the current towards the drain.. I thought about putting something over mine before I figured that my pond is pretty well balanced with absolutely no management so why mess up mother nature..

I believe in catch and release. I catch then release to the grease..

BG. CSBG. LMB. HSB. RES.

[Linked Image from i90.photobucket.com]