Guppy Emergency

[new2fishies]

I have had a tank of regular (?) guppies for years now. This weekend I wanted to get them some new decorations and add a few tequila sunrise guppies for variety. I cleaned the tank, the new decorations and the rocks and put everything back together. I used the same water I have used the other zillion times I've cleaned the tank. Now my native guppies are dying by the dozens! Today alone I have taken out about 35 that have died. I don't know what could have happened! I'm so upset. I got all the supplies at Petsmart. I'll be taking my guppy bodies in to get reimbursed, but that doesn't help me solve the problem. Does anyone have any ideas of what could have happened?

 

[Inchworm]

Does anyone have any ideas?

 

[Curiosity101]

This may sounds extremely ridiculous to you as you've kept fish for so long so probably already know this but... did to replace all the sponges in the filter or something like that?

 

[Malt_Vinegar]

did you clean the filter media/sponges in tank water, or tap water?

 

[craig855s]

did you change too much water at once and make the tempurature drop right down to cold tap tempurature?

 

[orangefish]

The new decorations could be the cause of it? They might be made of something that's giving out toxic chemicals- I read it on here once before. Correct me if I'm wrong, but it might be worth removing them?

 

[fishnovice]

Unless you made a mistake and rinsed filter sponges in tap water which would kill off the bacteria, the new decorations are the most likely cause. Remove them immediately and do a very big water change, maybe 75% to remove any toxins they may have released. Unless you get used ones, it's always best to soak new decorations in a bucket for a few days first to see if paint comes off or they discolour the water and make it smell funny.
The other possibility is Old Tank Syndrome (look it up, there are links somewhere on this forum). {lease don't be offended , I'm NOT saying you had a dirty poorly maintained tank. Basically if the fish have got used to a tank with blocked inefficient filter and infrequent water changes, the shock of sudden big water changes that alter the water chemistry can kill them. I've lost newly adopted rescue fish that came from poorly maintained tanks and died within a few hours of putting them in my tanks which have strong filtration and get 30% weekly water changes.These days all my "rescues" are kept in quarantine for a few days in their old tank water diluted gradually with fresh water every day until they get used to 100% clean water before they go in with the rest of my stock.