So about two weeks ago I got a few cichlids and they were doing fine until about two days ago. They’re kinda just floating in the water and on the bottom where they used to swim all over before. I already had a death of a bristlenose catfish so I checked the water. Nitrate is zero, PH is about 7.0-7.5, but the general hardness was a little high. Would that cause the fish to stop swimming? If so, please let me know how I can fix this.