Why do tanks crash?

[Beverly]

Our 180g crashed when we had it several years ago because one of the critters died and released toxins.

We thought "The Thing" was cool when we saw it at the lfs and were thrilled and agog to have it - whatever it was. It was orange, about 1.5' long, hollow, and looked like some kind of wierd and wonderful worm - or something. Needless to say, because we didn't have a clue what it was, we were hoping it would filter-feed itself with the food we fed the fish. Don't actually know if it ever ate, even though we watched it during feeding times. It didn't have a mouth that we could see so how could we tell?

So, one morning at feeding time, I noticed dead and dying fish and pretty much panicked. Looked all over for electrical and other problems, but there weren't any. Then it dawned on me that the orange thing was missing. Yes, it had probably died and its toxins were killing our fish. Luckily I had a whole bunch of RO water in storage containers and quickly whipped up NSW. A few large water changes later, our fish had stopped dying, but we pulled quite a few dead ones out. We were devastated, to say the least.

LESSONS LEARNED:

- NEVER impulse buy ANYTHING for a reef or FOWLR.
- Remember that Google is your friend, so research the living heck out of anything you see at a lfs or online BEFORE bringing it home.
- Ask questions after doing research to clarify anything you have even the slightest concerns about.
- After research and asking questions, NEVER buy anything that you think won't fully thrive in your tank.

[Aquattro]

Partial crash due to moving a 75 into a 150 and not having enough new water. By the time iI sorted it all out, I thought I was good, but woke up in the morning to a house smelling like dead acropora! Milky white tank, and downhill from there.