bz I was not thinking about ice. \:o I think I would take a few buckets of water from your other pond and put them in the new one to seed it and put in some brush. You should get some fall/winter plankton type growth. I would also try to keep the snow off of it so light can get in and help production. I assume you are not going to keep the ice open but that would help also along with clear ice. But first I would check on what they eat and need to survive. I will see what I can find.

http://www.epa.gov/bioindicators/html/amphipods.html

Indicates Bruce is correct. I also saw several references to them eating left over fish food. \:\)