Retics grow at an amazing rate, often reaching 8 feet or more within the first year. As a result, buying a snug fitting cage for your hatchling and expecting it to stay in there for much more than a month or so is unrealistic. The important thing here is to be prepared with each next size of vivarium ready as your snake begins to outgrow its old enclosure. When your snake reaches adulthood and a large size it will significantly reduce movements so trying to provide a space for the animal to wander constantly is no longer necessary. As long as the animal is granted access to a larger space at regular intervals (such as a snake room) then this is likely to be enough exercise to promote a healthy lifestyle. A size of 7x3x3 for adult pet retics is usually a good rule of thumb, so if you don't have this space to devote to an animal then please don't buy a hatchling.
This is a tropical species from Asia and is generally found very close to the equator. As a result tropical temperatures of 90 - 95F in the warmer end are a good average to work from. However it is worth noting that due to the size of land this species covers some localities and specific snakes will be happy with variations on this. A maximum I would work with is 105F and this is only for those animals that spend the majority of there time basking at lower temperatures. The act of basking itself is carried out to increase the body temperature of the snake until it reaches a workable level for the snake to begin its daily routines. A constantly basking animal is in need of a higher temperature spot and one that never basks requires this spot be lowered by a few degrees. Spending a few days with your snake and getting the temperatures just right for the animal will pay dividends later on. The cooler end should be of no less than 70F and should be a maximum in the low 80’sF to allow for proper thermoregulation cycling.
Again due to the origins of this species the humidity levels are classed as tropical. They can often be found in rainforests or by streams and rivers, both of these habitat areas have high humidity. Therefore the humidity within the vivarium should be maintained at 60-80%. There are several ways to achieve this, including strategic placement of water bowls (close to a heat source) or misting the area with a spray bottle. There is also an option of a "damp" box. This is usually a box filled with wet moss or newspaper designed specifically for the snake to enter as and when it comes to skin shedding. For those more technically minded, humidifiers regulated on timing circuits can be used to great effect.
Which ever you chose you will have only until the snake begins to shed its skin to perfect your method. If the levels are too low you will find the skin comes off in lots of pieces often leaving chunks on the back of the snake. This will have to be removed manually, which if you have a large nervous snake is far from an easy task. Often at this time many keepers raise the average levels by increased misting of the cage to ensure a clean and healthy skin is produced.
There are various ways of heating a vivarium, ranging from heat pads/cables to ceramic bulbs. These are all commonly available from most pet shops. Heat rocks are unsuitable and can be extremely dangerous to the animal as they lack the sensory perception needed to feel how hot the rock is, which can result in severe burns.
Whatever method you use to heat your vivarium, always make sure that the snake is unable to come into any direct contact with the source. If necessary use a protective cage to separate the immediate area around all types of bulbs, ensuring there are no gaps. Mats and cables should be placed on the outside of the housing to remove any chance of contact leading to burns. This also eliminates any problems that can occur through a faulty item or incorrect wiring. No matter what type of heat source you use there should always be a thermostat within the circuit, to control the temperature at a specific point within the vivarium. The heat source should directly warm 1/3 of the cage with a basking floor temperature higher than anywhere else within the environment you provide. Use a thermometer to gauge this accurately. It is essential to allow the animal an area that provides an optimal basking temperature and a cooler area so that the snake can thermoregulate.