Neon Tetra Disaster

[thefaxmachine]

OK, just went to check on my tank before heading to bed and I find three of my fish dead!

2 Neons and 1 Guppy


Earlier today all was fine and I checked their water (PH 6.6, AM 0, NI 0, NA 10) and then did a 20% water change as per my usual weekly routine with this tank. Done every Tuesday as its my day off work.

Its a 60L and contains 10 Neons, 4 Guppies and 3 Corys.



So, in horror at finding my fish in this state - the remaining neons look lifeless and the guppies seem to be hovering at the surface although they don't look like they are gasping for air. My Corys seem OK (I think) - I retested the water (as above except NA which is between 0 & 10), I've just done approx. 60% water change...

Any idea whats gone wrong? I did remember to declor the water and I use the API Master kit for testing. The dead fish (apart from being dead) look fine - no growths/damage to their skin etc.

I think I'm in for a sleepless night!


E2A: Oh, my! Just gone to check and I have another dead guppy! HELP

 

[thefaxmachine]

Woke up to find all the remaining Neons and Guppies dead!
What the hell happened?
My three corys are still alive though I think they are surviving rather than thriving as they ain't doing much moving compared to what they used to!

 

[Zeirath]

Not a fish expert but my guess is somehow some sort of contaminant got into the water, fly spray or something I dunno @_@ for all the fish to die like that with no physical symptoms it would be my best guess.

 

[thefaxmachine]

So, i remove the remaining dead bodies from the tank and one neon tetra springs back to life!

I'm left with 3 corys and 1 neon tetra in this tank. It looks so pityful! The poor fish!
I am so gutted.

So I've done a total water water change just to be on the safe side - however, I don't know how my water could have been contaminated as I make a huge consciencious effort not to use chemicals around my fish or the areas/equipment I use to prep their water/tanks!


I knew this tank was running too smoothly as I've had no issues with this particular setup for AGES!


What should I do now? One neon tetra not only doesn't look great but it can't be good for the poor fella to be alone. How long do you think I should wait before restocking?

 

[Geoff1991]

Wait until you figure out the problem, solve it then restock is what id do.

Edit: Theres always the chance there was nothing wrong. Neons and guppies arent the hardiest of fish due to inbreeding and stuff.

Also test your tap water. Maybe a drastic change in the parameters caused it. Just to cover all the basics first.