all my cardinals are at the surface?

[Tiggs]

this morning i found all my cardinal tetras (about 30) at the surface...every now and then they dart down but seem to return to the top. They dont seem to be "gasping"....could they just be eating the surface film??

the ph is 6.5, Co2 was off overnight, water temp has been too high but been coming down over last few days...they have never done this before!

 

[breezer40]

Have you tested the water for Ammonia Nitite and nitrate?

 

[Opcn]

There are three reasons for fish to be at the surface

1) They are eating, however the surface film is not edible to tetras.

2) There is some sort of gill damage possibly the result of NH3 or nitrite

3) The Disolved Oxygen content of the water is low, I suspect this pecause of the time of day the event occured, gill damage is more prevelent at the end of the day after the fish have been darting about for several hours, durring the night all the oxygen producing plants and algea in your tank become oxygen consumers which can be particularly dangerous for those using CO2 injectors, Also you said you have a surface film, this impeeds the tansfer of O2 from the air to the water, add some activated carbon or do some water changes or atleast skim the stuff off with a large spoon, then add an extra air pump and run it at night, the extra O2 will help everyone at night and during the day you can shut it off so that your plants dont starve, either that or every night reposition the output from your filter to the surface and every day point it back down.

HTH

 

[Tiggs]

ok....surface skimmer arives today so that will sort the film.

if i set an airstone to bubble away atfer lights out will that have any negative effect on my planst /co2 or does it just not matter afetr dark?

T

oh, i assume there is no way to check for o2 levels like there is with co2 via KH and PH?

 

[Tiggs]

i had the airstone on all day yesterday and by 4pm the fish were fine (except 2 dead tetras).......air ran all night but this morning they are all back at the top again. Could it be that my air was simply not enough? it was a gentle tricle of bubbles as opposed to a "full on" air wall type display!