Originally Posted by thedukeman
I was told that the skimate was so thick that the fish could not breath.
I think you'll find it was the DOC
/proteins trapped at the waters surface. The build up at the waters surface will form a barrier preventing proper gas exchange. While a skimmer is definately a plus it was the skimmer box removing that barrier that would have been the improvement, not the skimmer itself. Although the skimmer helps remove DOC
from the water column which also stifles available O2
, a powerhead aimed at the water's surface would have accomplished the same goal.
Then when the lights went out they went back to the top, swimming on their sides. (the temp drops and no oxygen is produced)
Cooler temps hold more O2
not the other way round. O2
is definately supressed after lights out but it's not the drop in temp. The lights cause algaes within the system to produce O2
during the day and much like houseplants without light they produce CO2
at night. It's the CO2
that lowers available O2
. That combined with the slime trapped at the surface would have been your issue. In short, improper gas exchange.