tank killing sponge, help!!

[Rsk8r4lif]

So a friend of mine got a very large yellow tube sponge at a LFS. the sponge was fine for a day or so, but then after that it turned the water completely brown, killed pretty much everything in the water, and also spiked the ammonia levels to an extremely high level. the water also smells horrible sort of like a back bay where you have like mud and grass kind of rotting sort of smell. Does anyone haev any ideas as to what might have caused somethin like this? we thought maybe something was dead in the sponge that was killing the water, but we cut up the sponge and nothing was in there. Does anyone else have any ideas? quick help would be awesome, thanks!

[TKByrnes]

Im pretty sure that as soon as a sponge hits the air it is done for and dies. that is causing your tank to cycle. how long has the tank been setup?

[Peter Eichler]

Decorative sponges rarely live in aquariums since they've usually been hacked off a rock, exposed to air, and mishandled in general. A decent size sponge could foul a tank pretty fast. My suggestion to you and your friend, avoid sponges other than small healthy pieces that come in as hitchhikers.

[Rsk8r4lif]

yeah he's just a guy i knew that wanted me to ask. but yeah it was a huge sponge, and it seemed perfectly healthy, for that matter, it seemed perfectly healthy after the tank was totally messed up, it was the only thing doin ok. but thanks for the help