Yes there are several scientific websites that sell most of them, the Malaysian shrimp you can get from several suppliers, the fingernail clams and salamanders would be local harvest (which I know could be kind of risky and is frowned upon), Red Ribbon leeches (non-blood suckers) I think I found from a bait supplier.

From all the research I've seen they are all tolerant to the water conditions. I do not think any would be invasive they are all native to the larger area, just not found in all ponds, and probably would never make it to mine, especially not at the beginning when they could mass produce, become self-sustaining and feed my food chain.

Also, there's no runoff into other waters. You got to do some digging to find where they sell them, and find information on them. I can PM someone who's interested. I'm just not sure if it's worth the trouble to add them or not. They are not real expensive or anything, so you wouldn't be out much. I'll be the guinea pig and keep good records and let everyone know how it goes since I haven't heard much push back.