Breathing REALLY heavily!plz help

[goldfish]

NEED YOUR HELP!!
my tank is 5ftx24x30(high)!!(540lts)
its a fuly planted tank,,with hairgrass in foreground, anubias everywhere on wood,amazon and crypts!
i've got 9 discus, 2 altums angels, 3peruvian angels, 30 cardinal tetras, 2 SAE, 4 clown loach, 3 cory's, 2 siamese fighting fish

the last 2 weeks i have noticed that ALL my fish are breathing really heavily except for the fighting fish which is not moving its mouth at all!,,,the discus gills are fanning very fast!!,,,,i have no idea what is goin wrong!,,i notice something might be wrong so i checked for ammonia level,it was very low on the indicator test,near zero,or zero!
I did 25% water change,gravel vac aswell!
my water temp is 28degrees
the ph is at 6.2
kH is 2
i put in Aquamaster Para-cide(trichlorfon) and still no improvement after the 1st week,all fish still breathing heavily.so i did the water change again, and then i used Melafix becuase the altums got abit of the cotton growth on its fins!
all the fish are eating normal from the feeder cone.
i thought maybe there might not be enough oxygen so i use my 700lph powerhead to spray near the surface of the water for movement.still breathing heavily.
my filter is the eheim,i cant remember the model number,but its the biggest model available,uses 50watts i know!!
so if u have any idea what might be causing the fish to breathe so heavily,plz let me know!!

[goldenpigeon]

it could be a couple of things. flukes or not enough oxygen. are you running co2? if so discontinue use for a week or 2.

start by getting lots and lots of surface filtration in there and really break up the waters surface to get lots of oxygen in there. this will help them recover much faster.

cant recomend to much more without feed back. hope they r ok

[goldfish]

yep,,,im running a full CO2 unit,the Milwaukee pH reader,solenoid etc!!
i am running it to keep the pH around 6.1 because of the Altum angels.
i can turn off the CO2 for a couple of week because i have just bought some Sera Peat to put in the water!..it will keep the pH and kH pretty low i think!!

since i have the powerhead running on the surface since thursday, all the fish are breathing slightly softer,not as hard as before, but still it doesnt look right to me yet!,im sure they can breathe slower!

i will turn off the CO2 to see how it goes!!

[Merrilyn]

Try adding a couple of airstones to that tank. You have a fairly heavy fish load in there, and all those fish require high oxygen levels.

The more oxygen you can provide, the better.

Hope that helps.

[goldfish]

i found the cause as to why my fish were breathing so heavily. i got one of those CO2 against KH chart.

i tested my KH again and it was basically 0 or 0.5,less than 1!
goin according to the chart, with a pH of 6.2 and KH of 1 or less, the oxygen level is very low.
i therefore slowly raised the pH up by one each day up to 6.6
the fish are not breathing heavily now!
lucky i have a CO2 unit set up to adjust the pH, makes it so much easier.
and also to get the pH up from the 6.2 to 6.6 , i basically put the powerhead filter spraying on the surface.


now have to just make sure my discus dont die from worms. i think its anchor worms, theres some mucus on the body aswell, just treated fish with Trichloroform.seems to be getting abit better colour now.hopefully it gets well so i dont have to use metro.