Because the fish crowd together a lot, some things stay hidden underneath the veil of fish bodies. For migrating we try to catch the smaller fish, so we take out the water to a low level.
Last time, when we did tower 1, we dug up a lost air stone, a cap from an automatic feeder and a dead fish that apparently didn't float and already showed some rotting signs.
This time its the turn of tower 2. Let's clear the dirt out!