TJ says it much better than I and he has the experience first hand to back it up. Thanks TJ!

Crayfish, there is a recent thread of someone who ordered them and had no issues. I don't know what type they were. The preferred type is softshell. But as TJ said, especially if you have rocky structure or dense weeds to hide them, they populate more than rabbits and then take out your vegetation and stir up the water, especially in a smaller pond. You would be best to wait till the SMB are big and aggressive.

Gams, let us know, anyone else on the forum know if gams live under the ice in OH (Indiana, MI, etc?)

Spotfin are a type of shiner. Bill Cody has two sources he knows of if you are up for a road trip. I know of no one who ships them but it is a mystery to me as to why since they are super hardy, readily take pellet feeding and reproduce readily in ponds with crevice structure for spawning surfaces. I'm told they are native in OH ponds and creeks so that might be your easiest source but I have no personal experience with that.

Your worries about GSH are correct and TJ brings up several other worries that might make it wise to never start down that road. I'm in year 5 of my GSH. I see less and less as I think the older females are probably sterile, but my middle size GSH do compete with the YP for pellets. I'm sure my GSH are cleaning up on YP babies and any potential RES babies. I don't mind so much on the population control for YP as I have a smaller pond than you and also stocked 100 YP. However I have harvested about 30 eating size and the last few years since I purposely did not put in any predators yet I have removed the majority of egg strands that I could get to without wading.

I have no predators for the larger GSH but hopefully that will change next summer. If I could have started with FHM and Spotfin shiners I would have so if you do FHM and some shiner species captured or purchased locally you will have a very nice pond set up.

I do believe Shorty is targeting his larger GSH through angling so his SMB must not readily keep up with eating the larger GSH.