Robyn,

1. Are there species of freshwater shrimp that would overwinter in my pond - maybe with just a mild amount of salinity - so little as not to harm plants?

I don't trust any crabs or crayfish - like i said before: snap, snap


2. As for fresh water clams and muscles - i notice that there shells litter the bottoms of streams and lakes - when they die, they cause water quality problems i bet.

Here are the questions concerning clams and muscles:

1. will they be a problem when they die - and you dont find them - maybe i should have a crayfish, after all....
2. how many would you recommend for a 1500 gallon pond?
3. can i put all of those, how ever many, in a single plant pocket of very small gravel designed as a clam bed? maybe 2' x 2' for 10 clams.
4. with a few gold fish, will the clams be a problem as when they breed the few gold fish i have will be a host to their larvae (to all other readers of this post: juvenile clams are minute parasites in suspencion that cling to fish)? In that case, i wonder why they don't warn people of this at all those pond stores - unless, its not really a problem.

"1. Are there species of freshwater shrimp that would overwinter in my pond - maybe with just a mild amount of salinity - so little as not to harm plants?"

Yes, there are native freshwater shrimp but good luck finding them for sale! There are many species of ghost shrimp and some are able to overwinter in the pond. Most of the ones sold in pet stores are semi-hardy but probably will not live over winter in your zone. I did put some in my pond the first few years but I assume they were all eaten and any survivors died over the winter. If you have fish, they'll just eat the shrimp.

"2. As for fresh water clams and muscles - i notice that there shells litter the bottoms of streams and lakes - when they die, they cause water quality problems i bet."

It depends on the mass of dead bodies, the volume of water, and the movement of water in the system.

"1. will they be a problem when they die - and you dont find them - maybe i should have a crayfish, after all...."

It depends how many die. If you just have a few, they probably wouldn't cause a noticeable problem.

"2. how many would you recommend for a 1500 gallon pond?"

I've never had clams or mussels. They can be intermediate hosts to some fish parasites as well so be aware of that. If you get them, they need to have pond water that has algae and microorganisms in the pond to eat so the pond can't be too clean. Don't put them in a new pond for a few years. They need a bed of sand in the bottom like in a plastic cat litter pan. I really don't know how many you should get. It depends on costs, room, and how much suspended food the pond has.

"3. can i put all of those, how ever many, in a single plant pocket of very small gravel designed as a clam bed? maybe 2' x 2' for 10 clams. "

That might work. They would have to be moved below the water freeze line in the winter. Also, if shallow and you have predators like raccoons, they'll eat them.

"4. with a few gold fish, will the clams be a problem as when they breed the few gold fish i have will be a host to their larvae (to all other readers of this post: juvenile clams are minute parasites in suspencion that cling to fish)? In that case, i wonder why they don't warn people of this at all those pond stores - unless, its not really a problem. "

"Baby clams" live as parasites in the gills of fish. Unless you have a ton of clams, this will probably not be a problem because the parasitic mussel/clam larvae usually do little harm to their host.