Neon Tetras hiding at bottom of tank

[AJorz]

Hi, my son has a tropical tank with 5 Neons Tetras in it (was 6 two days ago). The problem is they are all showing signs of stress by doing a shivering thing on the spot at the bottom of the tank.

They are in a 21L tank which has been set up for several months with a small fluval internal filter and a shop recommended heater that is set to 27°C.

I do regular water changes using only Super Fish Aqua Health to remove chlorine levels. I change about 20% of the tank water on a 2 weekly basis.

Water test results this morning were.

CL2 0.8, pH 7.6, KH 6d, GH 16d, NO2 0, NO3 25

 

[AJorz]

Also the tank has an air stone. Any thoughts at all?

 

[MurderComplication]

I would try to get the nitrates down to 10-20, and I keep my neons at 24 and they're very active. 27's more of a breeding temp. Sorry I'm not much of a help.

 

[AJorz]

Thanks for reply. I have turned the temperature down to 24°C and done a 50% water change. will post back.

 

[MurderComplication]

I just thought of another possibility that somehow never occured to me, even though I just fixed this problem in my own tank xD
Bump the number up to 10, they'll feel safer and there as well as be more active. I do find that, for me in my 55G, that they stay in the bottom 2/3rds of the tank as well.