Remember the most crucial part to keeping fish alive is not letting them go 15 minutes without sufficient O2 in the water. Aeration directly addresses that.
Removing fish will help cut the O2 demand as Zephyr shrinks. Removing larger fish is doubly helpful - larger fish usually suffer from low O2 before smaller fish (of the same species), and larger fish have a greater Biological Oxygen Demand than smaller fish (both direct - what they use through their gills, and indirect - from decomposing their waste products).
"Live like you'll die tomorrow, but manage your grass like you'll live forever."
-S. M. Stirling