How come>>>>>>>>>>>>>>>>>>>>>>>>>>…

my geckos like 2 stay in the littlest house they had a medium size 1 they diddnt like it so i went and bought a large 1 and they wont even look at it AND DONT SAY WELL TAKE THE SMALL 1 OUT BERCAUSE I DID AND THEY WILL JUST LAY OUT IN THE OPEN AND NOT MOVE ALL DAY IF U CAN HELP PLZ Z DO I Have a 20 gall tank