hi, :welcome:
agree with Brengun, test your water for amonia, nitrites and nitrates. There is a site here to better ask your questions, many members will read it and you will need to mention how long the tank has been set up for, how big is the tank, what other fish are in the tank, what kind of filteration using, etc, as much info as possible , so try the ''health '' site here so members have a better idea of what is going on. Hope this helps so you can help your ''buddy''. good luck with him .