A pH of 7.5 is fine for the peacock.
What is the GH of the water?
Your water supply company can tell you the GH and KH or you can check their website. Find out what the test is measured in too (ppm, dGH or something else).
If your water company can't help, take a glass of tap water to a pet shop and get them to test it. Write the results down in numbers at the time and find out what unit the test is measured in (ppm, dGH, etc).
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If fish are rubbing against objects in the tank, there is either a water quality issue or an external protozoan infection (white spot, velvet, costia, etc).
Post pictures and video of the fish so we can check them for disease.