Maria asked 2 months ago

I have a blue crowntail betta fish. I bought him from Petsmart and his conditions were not great however, he seemed the healthiest and the most interactive. I have had him for about a week and a half. This is my first fish. I have him in a 5.5 gallon tank with a low flow filter and a heater that keeps the water at a constant 78 degrees. I am doing a fish in cycle. I have done one water change and did about 50%. I have tested the water twice and all my chlorine and ammonia levels are safe but the hardness in water is high and it says i have alkaline metals but does not say if that’s unsafe. I do use a water conditioner. When i bought him he had white tips on two of his fins. (they were the longest fins on his side) He also had a little bit of fraying tips. I assume this was fin rot due to his condition in the store. He is not lathargic and is very active, constantly swimming around the tank. I feed him pellets, peas (he was constipated and read this could help) and a blood worm for a treat. I also fast him on fridays. He shows no lack of appetite. His color is blue, black, and a purplish color. He also had a slight hint of red. I had assumed this was just his color but now i am considered with it being ammonia burns. When i woke up this morning to feed him he had a bright red spot on one of his fins that have a white tip. It looks as if that the fin is growing in that color by the location of the red spot. I have red several different articles each saying something different. Can you please help me identify what this is and if he is sick?