In normal situations like this I would suggest not adding animals yourself. Any non-native animal, or even native animals not collected locally, could cause considerable damage to local populations. There are many diseases that are currently threatening amphibians and by adding your own animals it is definitely possible to contribute to the spread of those diseases and the decline of local animals.
The best solution for amphibians in man made ponds is to make the pond a suitable habitat so that local species move in and use the pond. Man made ponds are normally perfect for this if they don't contain fish and have some suitable shoreline vegetation.
Unfortunately, the fact that your pond is stocked with fish basically will keep you from adding any amphibian or many other animals. Amphibians prefer to live and breed in fishless waters as the fish are excellent predators of larvae and eggs.
If you want amphibians in your backyard you would have to either remove the fish or create a second pond that has no fish. Encouraging the local amphibians to colonize your pond is the way of choice here. Stocking the pond with amphibians, be they native or non-native, is a bad idea ecologically and may be illegal.
