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Question
The ph was at 7.0, the nitrite and nitrate were both really low, i dont know what the ammonia was cuz my tester kit ran out, n=but none of my other fish have ever had a problem with it. The hardness was at around 4 but idont know exactly. His heater was set at 78 degrees. I kept everything the same from my previous fish and they were fine. My old betta was 5 yrs old when he died cuz my little cousins kept tapping on the glass. :( But idk what else to add so if there is any more info that you need just let me know and i will try to find out. :)

Answer
Tara,

As far as nitrites go, the reading has to be zero at all times just like the ammonia. If the nitrites were up I am guessing the ammonia was too. The ammonia is cut down to nitrites and then to nitrates. The nitrates should be no higher than 10-20ppm. When I am told the water is 78 degrees, I have to assume you have a heater that says it keeps the water at a certain temp. Those types of heaters never work right and the water is usually around 70 degrees.  The heater has to be set at 80 or 82 degrees at all times. The best heaters are the ones that you set. It has a dial on the top and you pick the temp you want. Betta's are tropical and need warm water.I would think that there were a few things contributing to the death of your fish. These fish are very hardy since they live in stagnant rice patties. I think the water perimeters were off, the water was too cold and no water changes were done while he was alive. It is very important that weekly water changes of 25% are done. When that doesn't happen, the ammonia and nitrites will spike causing the death of any fish in the tank. It is never a good idea to compare fish we had before to the fish we have now. Fish, just like people, have their own needs and things that did not happen to previous fish can happen to the new ones. It is hard for me to understand how he was ok one day and the next day not. Most if not all, fish diseases are a gradual unset. I am thinking he was either sick when you bought him or got sick soon after. Always pay close attention to your fish. If you are going to have a problem with your fish, the water is going to give you a heads up. That is why it is very important to test the water weekly. I hope this has helped and if you have any more questions don't hesitate to ask.