I did a water change and added some plants and redecorated my tank. I don't know if this is normal but I was checking it out and noticed most of the fish are breathing fast and opening and shutting their mouths. is this normal? ive never really paid attention. am I being paranoid or did I do something wrong.. cause my tigrinis cat is in this tank and it is one of the fish breathing heavily. fast responses please and thank you.