Please don't touch goethite

[SuPrBuGmAn]

I've noticed that quite often the blind crayfish are hanging out on the ceilings around here, then drop down into the water column when they are disturbed.

[Kelly Jessop]

I've noticed that quite often the blind crayfish are hanging out on the ceilings around here, then drop down into the water column when they are disturbed.

You are right they do hang out on the ceiling,and this may be for predatory protection,but typically their food source may be on the floor. There are some interesting suppositions about crayfish. It has been proposed that due to very low metabolism,some of the very large crayfish may be 80 years old-but I have yet to see the documented evidence.