what on earth is my Neon doing?

[Sal]

I have 4 neons in my tank and one if them is doing something a bit weird. Yesterday I noticed it was going round in circles, sort of stabbing at the water with its tail in the air. Does anyone know what this could be? Could it maybe be something to do with the water quality. The neon looks very healthy apart from the wierd activity and all the other fish seem very happy including the fry. Can anyone advise? Thanks

 

[Alien Anna]

This kind of "darting" behaviour can be a symptom of nitrite poisoning. Is your tank cycled? (if you're not sure, check out the article in my sig). Check your ammonia and nitrite levels anyway.

 

[platypus]

I've noticed my neons reeeeally hate it if the temperature gets too high - so maybe this is something to keep an eye on. I'd say anything above 82ºF will start to stress them out IME.