Hi, everyone. I have noticed my Celestial Pearl Danios have clamped fins and look sluggish and don't seem to eat well the past couple of days (and I've lost two today). I've done water changes, but my water is testing okay (other than high pH of 8.2 and it's super hard). Their shrimp, snail, and Endler's Livebearer tankmates don't seem to be suffering as much, if at all, from whatever ails the CPD. Any suggestions where to go from here? They have been in this tank since late January and seemed fine until recently.
20L with sponge filters, room temp, and a few live plants (that also seem to be dying slowly). The java moss and duck weed are doing great.