Cichlids Problem

[Porky p]

Hi, I have around five malawi cichlids and one ruby shark in my 55gallon aquarium, all the water parameters are correct and I fully fishless cycled my tank before adding fish!
Anyway recently my cichlids have been opening and closing their mouths constantly.
I can't see it being a lack of oxygen in the water as I have a nine whole bar along the bottom pumping air bubbles all day.
There is no ammonia and no nitrite, with around 10-15 ppm or nitrate.
I do water changes usually fortnightly but since this problem I've been doing them weekly with no improvement!
Any help will be appreciated cheers

Josh

 

[nellynelly]

Whats temp of tank? also whats actually fiteration on tank, is there alot of water flow on the surface?

 

[CezzaXV]

I agree with nelly. Some people debate whether an airstone actually causes there to be any more oxygen in the water. The best thing to do is have your filter output angled in such a way that it makes the water surface ripple, allowing gas exchange to take place.

 

[Porky p]

I have an external hang on filter and a internal fluval, which I usually tilt so that it creates surface agitation.
However I can only do that during the day, otherwise it stops me sleeping.
My temp is usually around 78-79

Is that too high?