Steve I read with interest the article on how some of the smaller fish may try to explore a new homw when doing maintenance on the Jewel filters. It is also something I had not thought of but will certainly bear it in mind in future when doing mine. It has never happened to me yet and hope it never does. I was once careless enough to forget to replace the cover on one of my jewel filters and wondered why, when looking at the filter from the front on one occasion I saw a juvenile Sevrum swimming happily inside the top above the sponges. It was like he was in jail as I was looking from the front of the tank, through the grill at the top and there he was, but none the worse for wear. Nigel