Hey guys I'm in Los Angeles ca zone 10a. I've been looking for small fish to add to the backyard pond that can take temp down to the 40°f. Right now I have mosquito fishes only but they are shy so I want to add other fish that have some color but around the same size. No more then 3in. Pond is about 3000 or so gallons with plants and algae. It is not being fed by me. It sustains itself. Most of the "cold tolerance" "unheated" aquarium fish can only be in an unheated tank when you have your house heated.