I guess my taking short-cuts in the water changing process killed some of my newer fish. All four of my relatively new lemon tetras went belly up after a water change. The rest of my tetras are all fine. I use the python/hose connected to the sink faucet, do about a 25 - 30% water reduction of siphoning the gravel (in a 50 gallon tank), and add the water back by reversing the flow (adding chemicals to the tank to treat the new water in the process). I've been doing my maintenance like this for a while over treating the water and normalizing the temperature of the water before adding it to the tank. That was always such a pain to pre-treat the water. I guess I'm used to the hardier fish who can handle this type of water change. The lemon tetras obviously didn't take to it...those little poor bastards. The autopsy didn't reveal the exact cause of death, though. I guess it could have been the variance in temperature between the water being added and the existing water, fish stress, pH fluctuation, etc... . Oh well...that sucks! I prefer fish where I can just add tap water straight to the tank and treat it. It makes fish tank maintenance so much easier. Maybe I should only do 10% of the water at a time under this method? I wonder if they would have died then? I liked them, too. I guess my water change technique is a bad way to go. Some fish just cannot handle it. I prefer the ones that can, though. I used to pre-treat the water in a 15 gallon bucket letting it sit for several hours to normalize the temperature but it slows me down and makes a mess obviously. Ah...the plight of a fish tank owner.
