i've learned a disheartenning lesson a few years back. i lost my 18inch jardini just coz i didnt check everything before i changed water. i did all the basics (antichlorine drops etc.), except i never took note of our area's water pipe system sched. i had no idea the water company was scheduled to clean and upgrade the pipelines in the area that weekend. i un-intentionally let in whatever chemicals those water people used in the process resulting to my jardini's demise. it was an honest mistake but i still feel bad about it coz i should have known and kept watch regarding everything that could affect my fish's water 
