Water: a bottle with a working ball bearing is the standard, because bowls get filled with bedding. Check the bottle every single day by pressing the ball - blocked bottles are a quiet, common emergency. Two bottles at opposite ends is sensible insurance for a group. A heavy ceramic bowl as a backup is genuinely useful, especially for older or unwell rats who struggle with a bottle, and in hot weather. Clean bottles weekly with a bottle brush and hot water; use white vinegar for limescale and rinse thoroughly. Refill with fresh water rather than topping up. Scatter feeding: instead of one bowl, scatter the daily portion across the substrate and shelves. It takes a rat several minutes to search rather than seconds to gorge, it spreads the food around a group so a bold rat cannot guard the bowl, and it uses the foraging instinct that a bowl completely wastes. Make it harder over time: hide food in paper twists, egg boxes, cardboard tubes with folded ends, a ball pit, a dig tray, or frozen into an ice block on a hot day. Portion, do not pile. Measure roughly a tablespoon or two of dry mix per rat per day and adjust to keep weights steady. Weigh weekly - the mix is right when weights stay flat and the food is genuinely finished.