If you cant get to the equipment I would start from scratch if I were you. Unplug everything and forget about everything that's there except for the pond itself. Buy yourself a new pump (the one you have is probably all corroded anyway), get a canister filter or make a simple DIY canister filter, get some sponge/mesh filter material and wrap it over the pump. It will act like a second filter in addition to your canister filter and it will provide any potential fish with oxygen. The King of DIY and AquaPros on YouTube have lots of videos you can watch on DIY canister filters! Go to your LPSS (haha made that acronym up, it's local pond supply store) and get yourself some Lillys. Lillys are excellent pond plants when it comes to Beauty but it also creates a way for your fish to be covered from predators. Ponds aren't very demanding and don't require much maintenance but you can look up some of the few things you'll need to do to maintain it. You need to cycle it of course and then when you want to start out with your pond fish i would go with comet goldfish because they are extremely hardy! Then I would get into koi. You can also try some native fish! Just beware of fish that jump... They won't make it...
Also having this pond is going to be a natural pest control. Contrary to popular belief ponds with fish won't attract bugs because your fish will gobble them up. Mosquitos are like the blood worms of the pond world so don't worry about that, they will be in the fish's stomach in no time. If it freezes where you live you'll need a heater in your pond unless the pond is 4 feet deep or deeper. Koi and goldfish can tolerate a freeze as long as the pond doesn't freeze all the way through to the bottom. During a freeze keep your pump running so it can still oxygenate the water. I've seen all my fish survive even when the pond froze over the top. Good luck and keep us posted!
NatureFish
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