Tank water and issues with fish need advice!

[Nedly]

I finished setting up a 50 gallon tank about two weeks back. My fish have been obsessing over the belly scratching thing, including my red tailed loach. I read online about different causes including "gas bubble syndrome" which described "over saturated" water from deep wells which I have. I noticed a mineral in the water that was floating on top, eventually the filter water pushes it down making cloudy water.

I did a 25% water change on this past Monday. All of my ammonia levels as well as nitrates and nitrites are all low, hardly above zero with a PH of 7.4. My temps have been right at 76-78. I also have a little aquarium salt and stress coat in there as well.

I had a couple fish pass since I set up this tank. I am not sure what it is but the water is rough. I checked it with a TDS water tester and it tested for about 120, compared to the expected 220 from city tap water. I am not sure what it is, and I have not noticed any parasites, though I do not know if they would be big enough to see.

I am heading out to get supplies here in a short bit. I need any advice anyone can offer, I have a pregnant swordtail in there and my other fish which have always been healthy are showing the symptoms of scratching, and I mean on everything including the bottom of the tank while they swim.

What should I do? If I restart and remove the current water what should I put in it to treat it? What supplies should I get?

 

[Nedly]

I decided to do a water swap of about 10% using a shop vac and taking the top layer of water off and it seemed to help. Though, when I went to treat some water to go into it I decided to boil some water to warm it up a little and there I found in the kettle a concentration of minerals that I also noticed in the water immediately after pouring in the hot water.

So I guess that is my issue. What is the best treatment for this? I mean to make my water better for the fish.

 

[Matt68005]

Its probably fungus not minerals, you cant really "see" minerals. Our water in here in Nebraska is very very hard and ph 8.4 and you cant see anything floating. Best advice if theres flotaing white crap its fungus and i reccomend methylene blue for a few days/week to cure this, then put the filters back in, stress zyme, and change the top layer of sand, as it will be blue. Idk a hell of a lot about water chemistry, but certain rocks like volcanic rock make it softer/less alkalkine.