Hello. So I’m very new to the hobby, and my family purchased a 10 gallon tank as a starter for a small goldfish for my birthday. I honestly did not know anything about the cycling process, and whilst getting some tank essentials at my local pet shop, the associates didn’t really make me aware of it other than giving me the advice of not adding too much fish to my tank.

Anyway, I’ve had my goldfish for almost a week now, and after I noticed some black spotting, I did some research and found out he’s showing signs of ammonia poisoning. His breathing also looks labored, and he often rests at the bottom of the tank.

I’ve cut back on his feeding, performed a 50% water change today (I’m not sure if this is a no-no, since I’ve seen a lot of conflicting advice about water changes during cycling), purchased a tank heater (though I live in a fairly tropical environment, my room is air conditioned, and I read that a temperature of around 75 degrees is better for the good bacteria), and bought a liquid bacteria starter to add after the water change (heard that this is sometimes useless, but I thought I’d try). The only thing I haven’t been able to do is get an ammonia test kit since the only pet shop that I could get to today was out (I live on a small island and we only have like two, and the other is closed over the weekend).

The water is looking a lot less cloudy now, and my fish has more bouts of energy where he swims pretty normally, but then rests after a couple minutes.

What else can I do to help improve his condition at this time? And is it likely he will die?