Feeding
The most common diet mistake is a colourful seed mix, because the animal eats the fatty pieces and leaves the balanced ones.
Base diet
A formulated lab block or pellet keeps the diet consistent because it cannot be selectively picked apart. Fresh vegetables and small amounts of fruit supplement it.
Water and portions
Fresh water daily from a bottle with a working sipper — check it actually flows, because a blocked sipper is easy to miss. Rodents overeat rich foods, and obesity shortens their already short lives.
Foods to avoid
Skip sticky sugary treats, salty human snacks and anything mouldy. Some human foods are toxic to rodents, so when unsure, leave it out.