lisamommy

Here is my situation:
I have a 22 gal tank running since Jan 17 (almost 5 weeks).
I used Cycle to cycle the tank and after 10 days I put in 3 serpae tetras. Then 2 weeks after that I bought 3 glowlight tetras. Then the following week I took a water sample in the to fishstore and had it tested and the guy said my water was "fine" so I bought a male platy. That was Tuesday and today (Friday) he was dead. Last night he didn't seen interested it eating but ate a bit, by evening he was hanging around near the bottom of the tank until the fin-nipper serpae chased him and then he moved. I thought his scales looked a bit white-ish last night but my husband thought I was nuts.

So my question is - could the "fine" water on Tues have changed to deadly by Thursday?

eta - we did a partial water change on Monday - could that have altered the readings?

Thanks.

Narcicius

First of all don't use Cycle its a terrible product, full of lies and deception. and in a 22 it would be possible for ammonia to spike from adding another fish and overfeeding. It seems as the platy was killed by your other fish, but I'm not sure.

capekate

Yes, your water condition can change very quickly. There are a lot of reasons for this and a few are:
adding new fish...
vacuuming an cleaning out a whole tank ...
changing out filter media....
and sure there a many more reasons for a water quality to change quickly.
Even in a cycled mature tank these changes can happen quickly and produce a mini cycle.
As above poster mentioned.. the cycle product is no guarantee to cycle a tank and is not recommended as it just does not work and can give one the false sense that their tank is cycled. Only way to tell is to use a very good water testing kit such as the API master...
Also, if you have tested the water, and it is fine, then its possible that the platy you just brought home was a weak one from the LFS and did not acclimate well to your tank.
good luck with your tank..
~ kate