First the Tetras

[FanOFish]

It seems there is something very sinister happening in my tank that's killing off fish. My signature shows what's left.....there were 12 black neons, 10 regular neons, and 3 small angelfish.

I found a new home for a very agressive large Pearl Gourami and replaced him with 3 small angelfish and an additional 6 black neons. Over the last week, two angels have died, 11 black neons, and 3 regular neons. I didn't see any disease or strange looking corpses so I figured it must be something with the water. This morning I took readings and they were:

Amonia - no trace
Nitites - between 0 and .5
Nitrates - 40
PH - between 7.2 and 7.8

These are pretty stable readings and the angels are too small to eat neons.

I did a 30% water change a couple days ago, and have lost some since then as well.....

Any thoughts???

 

[DrOizo]

Perhaps try a general treatment e.g intrepet liquisil or melafix. If there are no scaleless fish in the tank maybe also a bit of salt?

 

[Shizat]

The fish that you added aren't too hardy and these usually need pretty good water conditions to survive. The source of your problem is probably your nitrites. All your other fish are ok in the tank because the nitrites probably went up gradually where as the new fish you put in it became very stressful for them.

 

[DrOizo]

before you can say it is nitrites, how long has it been since the tank was cycled, I presume this was an established tank?

 

[Auslander]

Aye...I would have thought the Nitrites would be a good bet as to the cause of your woes. Your Nitrates look a little on the high side an all.

 

[Doggfather]

could be the nitrates, or maybe ph? those fish all like acidic wate...

 

[Idolz]

If you have high nitrate lvl add some live plants... it's fertilizer for them. When adding the new fish did you gradualy add aquarium water in their bag before?

 

[FanOFish]

Thanks for all the suggestions....

It is an established tank and the Nitrites are between 0 and .5 which should be in the safe range no?

I do have a couple clown loaches so salt is out.

I haven't lost anything in the last two days which may be a good sign.

It sounds like the general concenses is that the new fish had a problem that spread to some of the established tetras and two of the three angels???

I've been planning on adding some new plants etc. so next weekend will be a good vacuming and water change.

 

[bgraber]

Yeah, if you are saying the nitrites are at .5 After the 30% water change, they we're probably much higher Before.. Just a thought..
Also i'd think that if the tetras had something that spead and killed a few other fish, without treating it why wouldn't it spread to Everything in the tank? You may want to try and get a diagnosis on one of the dead fish.. Ask the LFS about that batch of fish.. Maybe they had some problems..