So I’m planning on getting a gecko soon but the largest enclosure I am able to get is the zoo med 25 gallon front opening and what I’m planning on doing is having a light for basking during the day and a heat mat for at night does anyone know if this is ok or should I get another light or something?
#can I have one light in a 25 gallon enclosure
harsh kiln
dry ferry
!guide this will give you plenty of info and it's backed up by science! I suggest giving it a read 
nova flareBOT
dry ferry
Heat mat is unnecessary unless the tank temps drop below 65⁰F at night. If you need night time heating I suggest a ceramic heat emitter as your first option and if you can't get that then a deep heat projector will work. Nqa
Heat mats also don't provide the proper nutrients and just doesn't give what Leo's need nqa
hybrid meteor
i would strongly advise against getting a leo with only being able to keep it in a 25 gallon tank - a tank that size is unfortunately just too small to properly house an adult leo. they just need more space than that, we recommend at least a tank that is 36x18x18 inches. we also would advise against heat mats as they are pretty inefficient & do not emit the right types of heat (can explain that more later)
i would recommend looking into a different type of reptile/pet to own if a 25 gal is all you can currently have. if you are able to own a bigger vertical tank, then there are many aboreal types of geckos you could look into! but lots of floorspace is important for leos