Third post on this subject. My betta suddenly got very ill in a tank where the only major change had been an older plastic ornament that I added after dipping in it boiling water for a minute or two. I had put my otocinclus in the tank with him the night before just to try out the pair, and they seemed to get along well. When my betta was hiding this morning I figured maybe the oto was bothering him, so I put him back in my community tank. I transferred him over in a little cup (he is spunky and thrashes quite a bit in a net). Thinking that there was nothing actually wrong with the smaller tank, I dumped the whole cup into the 10 gallon tank. The betta is now dead, and my best guess is heavy metal toxicity from the ornament (don't know how that is possible, but it struck too fast to be a disease and my levels are all normal). The oto never seemed affected which is another reason why I thought everything was normal (I added the ornament the same time that I added the oto, so he was in the tank with it for the same amount of time).
My question is if it is heavy metals, will adding a cup of water contaminated with it affect a 10 gallon?
My question is if it is heavy metals, will adding a cup of water contaminated with it affect a 10 gallon?