My ray seems stressed. He has been raising his front disc on the glass the whole day yesterday and today. I noticed this after doing a 25 pct water change on the tank. He would sometimes climb to the top then down again then raise his disc again on the glass. I also have 2 other rays in the tank and both are doing fine. What should I do to calm him down ? water parameters are all ok . He is in a 350 gallon tank with sump filter. thanks guys !



