I NOTICED A SORT OF "FILM" ON TOP OF THE WATER OF MY TANK & THE CICHLIDS WON'T GO UP TO GRAB THEIR FOOD. I CHANGED 60% OF THE CARBON (HOPEFULLY THAT'S THE PROBLEM!). CAN ANYONE TELL ME WHAT THIS IS ABOUT?? THANKS!!
If you don't have a lot of surface agitation by a bio wheel, HOB filter or air stone, you usually get a film on the top of your water caused by fish food or other pollutants. When you have surface agitation, it breaks up the film and the film can sometimes get sucked up by the HOB filter if that is the type of filtration you have. Is your water still at the top of your tank?
the lfs told me to agitate the top of the tank by airstones. I did, film's gone, more oxygen in the tank. but the cichlids still hesitate to eat at the top like they used to. they wait for the spirulina flakes to drop down & grab it. is this normal behavior? even the dominant one waits for it at the middle.