If you believe what you read about rocks on the bottom causing issues I can tell you moving the rocks will stir up muck, what some people consider to be the problem, would make the issue 100 times worst in the short term. If your fish died after doing this you might blame yourself, whether true or not.
I'm not one who believes rocks on the bottom always means poisoned fish. It is true that a pond with a lot of fish which are fed a lot produce a lot of waste and that can certainly cause problems. I'm talking about large Koi fed many times a day, putting pounds of food into the pond each day. But a pond with a few small fish, fed a little, isn't a problem. Very close to the way it works in nature. It works just like a compost pile, the waste breaks down into soil (called muck or silt when in water). Another way of thinking of it is cows in a pasture vs cows packed into a barn. In the pasture the waste load is light, has time to break down. In the barn the waste becomes a serious problem fast.
So not all ponds are the same as many people would have you believe.
I don't really like treating fish when I don't have a good idea what I'm treating. Good way to push a sick fish over the edge. But if you want to try the shotgun approach I'd start with the safest first. Salt baths are pretty safe if you're good at math. Basically salt can be used 2 ways. A high level can kill some parasites outright. Lower levels just cause the fish to produce more mucous than normal and can help push parasites and bacteria out away from the fish. Salt is far from being a 100% cure. It's used because it's cheap, easy and can help some things.
For medications you really want to read the label. I've read a lot of posts from people throwing everything at their fish and not realizing mixing some things is harmful because they were in too much of a hurry. Beyond that, without knowing the problem there's no way to know which would work. Your guess would be as good as anyone's.
You could try providing more symptoms here. Floating on its side? Does it swim? Does it eat? Is its body distended? How do the scales look? That kind of stuff. But I think it's pretty much impossible to diagnose these things in a chat. The best that can be done is give you some ideas you could research.
Hope it works out. Sick fish suck.
