Just wondering what ranks as your biggest disaster's / **** up's in fish keeping, could be pure bad luck or man made **** up's

also add the cost of it financially if you can bear it
For me in order of horror
1. Rio 300 that was full of water and fish, smashed onto my floor when the stand it was sitting on collapsed, it was not a proper fish tank stand, just an old chest of drawers.
So man made **** up there! I rescued all but about 2 fish. The cost to me was £200 for new tank of the same size and i also lost a heater (£10). But the main problem as you could imagine was 300 litres making a break for freedom, really ****ed my flat up for a good few weeks. I also cut myself badly and still have the scar from not being careful when collecting all the smashed glass! Numerous items of paperwork that happened to be on the floor got ruined and also the laminate flooring is permantly ****ed now, so the real cost was probably closer to £300 plus
2. Not sure what i was doing with about 25 Midas Cichlid Juveniles (about 1.5") big, but i had them in a 4 footer until i worked out what i was going to do with the them long term. One morning i woke up and all but x3 of them were dead. To this day i still dont know why, the others were gasping, so i guess itn was o2 related, but the filters were still running and in terms of inches per fish, the tank was not massively over stocked and the water readings were ok (ammonia, nitrite). I just remember taking the day off work, was quite traumatised just seeing so much death in the tank.
3. Well over a year ago, had some kind of internal parasite problem in a Rio 180 community tank, wiped out 50% of the fish over the course of 5-6 weeks, affected fish becoming skinnier and skinnier, mostly my live-bearers. It was after this i had a complete re-start, and spent quite a bit of cash buying lots of F1 Guppies and Platies from a guy who collects them direct from Mexico region.