water height

[Mordrake]

hi

does the height of the water level affect the way discus behave?

i have 4 wilds in a 20gallon tank with a height of 18inches.
when i fill the water level till 2inches below rim, they do not seem so active.
but when it comes to WC time, they become very active when the level is ard 8inches before refill. so i tried a change yesterday, i only filled to about 13 inches level and they seem more active than when it was at 16inches height.

anyone else have some exp on this?

[Carol_Roberts]

Is there more surface agitation so more oxygen in the water at 13 inches ???

[Mordrake]

i hv a sponge filter in the tank measuring 5inch in height and 4.5inch in diameter. including the plastic pipe on the sponge, the total height of the sponge filter is about 8 inch.
since the height of the air bubble outlet is nearer to the surface, i guess the surface agitation would be higher.

anything to do with less water pressure due to reduced height??