My lesson came in the from of trusting my partners mum to look after a tank for a 2 week period so my fiancée and i could go skiing for the first time. I gave a guided instruction for a week and also left instructions on the side of the tank. I got back and ammonia was through the roof, fish had been left to die and also left in the tank. Her dad was sick from the smell when he attempted to clean it out inevitably leaving this slurry mix for me to find on arrival home. The only thing that survived the mother in law were the juvenile and baby mollies. Needless to say it is now only the local fish store i allow to sort my fish while i am out of the island!