If I could manage to use one of the hints you mentioned to lower the temperature to 79, what do you think the ideal number of C. habrosus would be?

The tank is currently stocked with ghost shrimp, trumpet snails, and apple snails (Pomacea bridgesii). The apple snails would be getting a new home on account their pH and hardness requirements, and the larger shrimp would need to join them if the corys spawned.

The tank is moderately planted, and ...

I'm interested in setting up a species tank with one of the dwarf cory types (habrosus by preference). The one thing I can't adjust to suit their needs is the temperature. The tank in which they'd be living does not receive direct sunlight at any time during the day. It's not near any doors. It is ...