Hi,

my discus planted tank has a layer of oil on the water surface.

May I know how this happens and how to remove it.

I tried with a sheet of towel paper, but the oil is just too much to remove and it comes back after a day.

Any ideas why this happens? Also, I tried with water turbulence, but the layer of oil is simply too much, can't get rid of it with the water turbulence.

Searching around, i guess this is a layre of proteins, but not sure howit comes and how to remove it

I am feeding using tetrabits - granular food. This is a matured tank for 9 months and this oil thingy appeared 1.5 months ago till now.