Ok, so I think I might have found a way for each of my 2 Bettas to have a nice 10 gallon home. I can split this 20 gallon with an opaque divider. My mother has this old 20 gallon that she recovered from the basement. It has no hood or anything, it is simply a tank and stand. My mom claims it is cursed, everything she has ever had in there died, even a betta. Gone in days. So, I told her there might have been something wrong with the water. She said it always tested fine, and she did almost everything right. She cycled it with fish (this was before anyone knew about fishless cycling) did frequent water changes, never overfed, and understocked with compatible community fish. Is there anything I can do to make this tank safe? I have a feeling there is something like a virus or bacteria living in this tank. If I do 'uncurse' it, could bettas live in it with no heater or filter, if I kept up frequent water changes?
