Ventilation Questions in Enclosures and Barriers Posted November 5 · Report reply On 10/23/2019 at 2:54 PM, BeetleShelf said: Hi everyone! I have 5 small colonies right now, all with a heat gradient of 70F to 82F. Their tubs fog up pretty bad, and I only have ventilation on the top of the lid. I heard that cross ventilation is really important for roaches, is this true? Do I need to redo the ventilation on all my tubs? - Spencer It depends which species you have. My hissers have had ventilation on only the lid for many months and do fine.