house

Ive been searching for a while on what bulb would be ideal for my crestie, but all i can really find is "if your house is above 18 degrees, no need for one!" My house regularly gets below that. Can anyone help me out with the ideal wattage and type of bulb that would be best? Thankyou :)

These guys are probably our favorites of the species we have in house, in regard to coloration.