I don’t have anything to measurewater hardness, but my ammonia went up to 0.50 due to the food getting stuck under decorations and gravel not sure if this was the actual cause of my molly wiggling abnormally
If you contact your water supply company (via website or telephone), they should be able to tell you what the pH, GH (general hardness) and KH (carbonate hardness) are. If they can't help you, take a glass full of tap water to the local pet shop and ask them to test the pH and GH for you. Write the results down in numbers when they do the test. And ask them what the test results are in (eg: ppm or dGH or something else).
If the GH is less than 250ppm, you will need to add some mineral salts to increase the hardness. I recommend using a Rift Lake conditioner at about 1/2 strength.
Rift Lake conditioners primarily contain calcium and magnesium chloride, which increase the GH nicely. It also contains other minerals in smaller amounts and they are also useful. It will also increase the pH.
To use it you add some Rift Lake conditioner to a bucket of water, aerate it for at least 30 minutes and then use that water to do a water change.
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Ammonia, nitrite and high nitrate levels can cause fish to shimmy, but the most common cause is low GH or protozoan infections.
If you do a big (75%) water and gravel clean the substrate, it will dilute the ammonia and protozoans in the water and will usually help. But you need to make sure the GH is suitable and no more ammonia builds up in the water.
If the tank has been running for more than 6 weeks, and you haven't cleaned the filter in the last 2 weeks, then clean the filter too.