I have two.
First one: in our first tank, we had somehow acquired a mystery fish. I dont know what it was, and honestly it was so long ago i really dont see a reason to try and figure out what it was, but it looked like a female guppy, just a SLIGHT bit larger, and it was a solid olive-yellowy kinda color. Like a dull greyish yellow.
Anyway, we named it Odie, because it was small, kinda dumb (hard to explain. just trust me, it wasnt the brightest.) And we never hada real cover in our tank. We never really had any problems, either, though, so it was okay.
well, one day odie disappeared. About 3 years later, when we decided taht we wanted our christmas tree to be where the fishtank was, we moved the fishtank (which was kiddie cornered) and found a dried up odie plastered to the floor.
second one: My cousin and me had a saltwater tank together. It was a bigger tank, i never knew the size (i was younger and really didnt care haha that was my cousins forte at the time =P i just liked the fish's colors) but anyway, our brothers (my brother and her brother) decided that since it had to be moved, theyd do it without taking out all the water. They took out half of it - and it was a bigger tank - and tried to be macho guys about it.
well, the macho guys cost a lot of money and had to pay my cousin (and me, technically) the money to replace the tank which cracked, water and the stuff to put in it, new fish since ALL of them died, and he had to pay our grandmother who owned the house where it was kept for the damage all the water did when it seeped through the top floor straight through the main floor and into the basement.
heh. "macho" guys. heheheh.