Hi yall. Yesterday I came home to several dead fish, 7 ember tetras, a panda Cory, and a swordtail. This morning i woke up to a dead betta in the tank as well. I have a 40 gallon, with pleco, guppies, swordtail, and several coryadoras. My water parameters were all good, temp is good. Yesterday my betta was acting normal, she ate and was active within the tank. I'm not sure what's happening with my tank, and was hoping maybe somebody here had any insight or advice? I'm waiting right now to go to the fish store to get some medicine, as I was thinking maybe it's an internal parasite or something? Idk