I had them in the basement at one point in time, actualy had the whole betta breeding mess down there. the furnace backed up and killed over 200 newborn fry. we just got lucky that it didnt back up into the whole house, even though we have carbon monoxide detecters on every floor. the bettas got moved out of the basement and into a spare room upstairs after that.
these deaths are pretty far apart from the basement episode, so it may or may not be related. my betta with cancer I am pretty sure he came with the start of it, he was a freebie from a breeder, and had a miniscule spot when I got him, that spot just kept growing into a tummor. so I am fairly sure that the breeder knew that fish from that line were more prone to cancers, and just dumps the ones with the first sign of it.
it is also remotely possible that some sort of pestacide is getting into the water in trace amounts threw the well, we live on a rather large farm in the middle of lots of farm land. we do not drink or cook with our well water so it wouldnt bother us.
