Penguin Tetras And Black Neons

[superman1]

Hello

ive recently brought 6 penguin tetras and 6 Black neons and all they do is school at the top or breath from the water.

all my stats are fine and i have 6 cardinals who never do this and they just hang about at the bottom of the tank.

when one or 2 of the tetras decide to swim down to the bottom they all follow but more then likely they just follow eachother and breath at the top

wanted to know do these fish generally hang about at the top.

they are the only fishes that do this.

 

[Jpmc™]

They are little copycats.
For the breathing, you may want to check for ammonia and nitrItes.

Also, is the tank cycled? I'm sure it is. It's probably just stress from moving in, just give them a day, and if they are still doing it, then post in the emergency section.
Oh, and are they in your 240 L tank? It's probably overstocked, clown loaches need about 75 gallons each.

 

[superman1]

hello

yeh tank is cycled and has been up and running for a while. the filter has been running for about 6 months on a previous tank

it is in the 240 litre but stocking has changed as i fancied a move around

the rainbows have gone.

the danios have been reduced to 5 and the mollies have gone.

so current stock is

6 penguin tetras
6 black neon tetras
6 cardinals
5 pearl danios

1 red tail black shark
5 tiger barbs
2 3" clown loaches ( these will not be in here for much longer)
1 yoyo loach
3 pagasius catfish 4" (these will not be in here for much longer)
1 1" upside down cat

4 ottos
1 2" clown plec
5 corys
6 khulli loaches
1 chameloen shrimp

i know stocking sounds quite alot but all fishes are pretty small and the stocking will change
but
ammonia is on 0
nitrates are on 0
nitrites 0
ph is about 7.5
word is oh the high side of hardness

ive read somewhere the black neons need around 6ph.
is this true

my cardinals kind of behaved the same way when i first got them so am assuming its just because there new in the tank