Strange...

[littletankbigworld]

Here's what happened.

Saturday: After fishless cycling, removed about 85-90% of water in 20 gallon tank. Added a couple fish to the tank several hours later.
Sunday: My beloved guppy dies; I assume because he was sick for two weeks and possibly the move stressed him out too much. Bought two guppies and three Bleeding Hearts Tetras from LFS. One guppy dies an hour after purchase.
Monday: Other recently-purchased guppy is dead. I assume a bad batch of guppies. No tetra casualties. Water test reveals 0 ppm ammonia. My beloved molly dies after showing no signs or symptoms of stress or illness. Purchased 3 mickey mouse platies and 3 Serpae Tetras to school with Bleeding Hearts.
Tuesday: No casualties.

I am extremely curious as to why our molly fish died. All the water was totally normal. Nothing was wrong. It was a bit of a shock.

 

[homebunnyj]

How did you acclimate them?

 

[littletankbigworld]

Verrrrry slowly. Each bag took about an hour. Every 10 to 15 minutes I added a little bit of water from the tank to the bag.

Wednesday: No casualties.

 

[MissFishy]

Did the fish show any symptoms?

Check the ammonia that you used to fishlessly cycle the tank, did it have any soap suds, coloring, fragrance, etc? It should have just been 100% pure ammonia.

 

[littletankbigworld]

It is 100% pure ammonia. No surfactants. Nothing. Also, the nitrite reading is < 0.3 mg/l.

That is why it's so strange. She showed absolutely no signs or symptoms of stress or illness. Just died one morning. All the other fish are thriving, but she died. It's a mystery.

 

[Newman]

sounds like a weird case. maybe youre not testing for something else that causing the problem? (i havent tested for GH before and found out that it was astronomically high in my tank )

OR maybe when you changed 90% of the water, you took out a good amound of the bacteria...even though they normally do colonize on hard surfaces and the filter... just a stab in the dark.

Nitrite levels of .3ppm are low, but even presense will cause fish stress (it prevents repiration) or something like that.

 

[MissFishy]

You don't want to expose your fish to ANY nitrite poisoning, nitrite is actually more toxic than ammonia, both should always be at absolute 0.0. That may be your problem right there.

Another thing you could check, check the PH level of your tank water and the PH water of your tap water coming straight out of the faucet. Your tap water may have low buffering capacity which can cause PH swings which stress fish out. If so, there are solutions that DON'T involve using bad chemicals like "PH Down" or whatnot. Ask here before messing with those.