I have lost 3 of my most special fish in the space of a month and I'm losing one. Angel my elephant ear betta died first, then came Ash, my platy, then Loki, my black moor goldie, now my beloved betta Gordon is dying and there is nothing I can do. I just wanted to get this out of my system.
I'm so sorry for your losses, that's really rough losing so many in such a short period of time :'( I recently went through the same thing with my adult mystery snails, it's really hard. Do you know why you've lost so many?
Truly sorry for your loss, I couldn't imagine that happening to my fish and I have only had them for two months! You said you had a Black Moor though? Aren't goldfish incompatible with bettas because of the temperature difference? I have never had either though so correct me if I'm wrong.