How do I know when to give my ball python bigger rodent?

I realize that many plastic items will degrade in UV light, such as from the sun, and is harmful in the environment. However, a glass tank is simply not the healthiest option for your snake. There are millions of Ball Pythons, boas and other snakes housed in plastic tubs in rack systems and in PVC or HDPE cages that are healthy and long lived, including those in my own collection. A 3X2 cage would be sufficient for most male Ball Pythons. The issue with aquariums is not only the humidity and heat issues, but the limited distance from front to back that crowds an adult snake when they try to lay in a flat coil. As for your feeding question, you want to see a noticeable lump after the snake has settled the food into its stomach. A proper sized feeder is one to one and half times as big around as the snake is at the snake's largest point. Edit: Exo-Terra and ZooMed both make glass enclosures that open in the front. Each company has enclosures that are the right aspect ratio (wider than tall). There are both sliding and swing out doors available. I would heat such an enclosure with an Ultra-Therm heat pad mounted on the bottom of the tank. A thermostat is critical, but at least have a rheostat to control the heating device. If not, you risk your animal's safety, as well as your own. An uncontrolled heating device is a big fire hazard.

You should first feed it something small like something that is half of it's size. As the python gets bigger then feed it a bigger meal. Measure the python and every year, see how much it grows. Go to the store or place that you bought the python and ask them that question. Just buy 1 tank, the 30 gallon one, place the python in the tank and add a lot of things in it like rocks leaves food and plants. Just make sure the python has a small cave to creep in because reptiles love the dark. add heat and cold on opposite sides. If the python don't move in the cold area then bring it to the heat. You maybe already know the fact that when reptiles get cold they hibernate. Thanks for letting me help. I love typing and animals. Bye!!!

Overdose has a good answer. I don't notice mine having any significant bump in the stomach after eating. My snake is almost 2 ft long and I feed him small mice right now, and it's about the size of the biggest part of his body. You can move him in soon if you'd like. You can wait until he's about full grown to move him into the 30 gallon. He won't need anything bigger than that for the rest of his life which is awesome :). I actually don't use glass tanks, they don't hold the humidity in them well at all. I use tubs from Walmart (sterilite or rubbermaid) with their lids and drill holes in the side for air flow and use aspen for substrate and you can use a under tank heat mat or flex watt tape (ordered online) for the heat source. The tubs hold in the humidity much better since you need at least a level of 60% daily and 80% during shed.