Fishy Behaviour ... Need Help

[Mariposa]

I have had my tank set up since the begining of January, I had six tetras in it to help start the cycle and they were moved to a new tank last week. I bought a small school of rasbora (11) and they seemed very jumpy when we brought them home.
I thought it would take a few hours for them to calm down, but it's 5 days later and they still spend most of their time in a corner behind a plant. I tested the water and my amonia is zero, the nitrite jumped a bit overnight (which is weird because it's never done that before) to 0.3 and nitrate is within acceptable limits.
Also, one fish was swimming erratically this morning and died within a few minutes. I am not sure what is wrong ... but something sure isn't right. Any advice?

 

[diademhill]

I have had my tank set up since the begining of January, I had six tetras in it to help start the cycle and they were moved to a new tank last week. I bought a small school of rasbora (11) and they seemed very jumpy when we brought them home.
I thought it would take a few hours for them to calm down, but it's 5 days later and they still spend most of their time in a corner behind a plant. I tested the water and my amonia is zero, the nitrite jumped a bit overnight (which is weird because it's never done that before) to 0.3 and nitrate is within acceptable limits.
Also, one fish was swimming erratically this morning and died within a few minutes. I am not sure what is wrong ... but something sure isn't right. Any advice?

The tank cycled -just- with six fish & then you put 11 fish in - doubling the stock- so you have had spikes. The ammonia bacteria established earlier so could cope but the newer nitrite bacteria couldn't. Nitrite is toxic which explains the death.

 

[WILDER]

Need to get that nitrite reading down with a water change, just check for signs of parasites, like they have been sprinkled in salt, or a yellowish to brown dusitng on them, check the gill to see if they are red and inflamed.
Also check if they are flicking and rubbing against objects, check to see if they are laboured breathing.

 

[Mariposa]

Thanks for the speedy replies, I don't want to lose other fish.
I did a partial water change yesterday (before the nitrite spiked) should I do another today?
I haven't seen signs of ich or any other parasite or bacteria. Their gills do seem a little red in certain light but other times look completely normal, so I'm not sure if it's a colouring thing.
They aren't rubbing against anything or flicking. Also their colour is not brownish or yellowish, they look completely normal, just really timid.

 

[WILDER]

Justed wanted to check, you went into a mini cycle with adding the new fish, red gills can also be due to poor water quality, just keep an eye on stats, good luck.