Two behaviours will dominate: basking and diving
A young red-eared slider divides its first week between two extremes. When the room is still, it will haul out onto the basking dock and sit with legs splayed and neck extended, soaking up heat. The moment a shadow crosses the tank, it launches itself into the water and wedges behind the filter or plants. That dive is hardwired self-protection in a hatchling-sized turtle, and it fades gradually as the slider learns your movements mean food rather than danger.
Short feeding strikes follow the same learning curve. Many young sliders ignore food for the first two or three days, then begin snapping at pellets while staying close to cover. A slider that eats greedily on day one is the exception, not the standard to worry against.
Water does most of the work this week
More than any other pet in this group, a young slider's first week is won or lost on water conditions. The water should be warm, in the high seventies to around eighty Fahrenheit for a youngster, deep enough to swim and flip over easily, and moved by a strong filter, because sliders are messy and ammonia builds quickly in a fresh setup. Check the water daily and do partial changes promptly if it clouds or smells, rather than waiting for a weekly schedule.
The basking area needs to be clearly hotter than the water, roughly the high eighties to mid nineties under the lamp, with ultraviolet light over the dock as well as heat. A slider that cannot get fully dry and warm is at risk of a soft, unhealthy shell and a poor appetite, so a youngster that never basks deserves a setup check before it is labelled shy.
Feeding happens in the water
Offer food in the water itself, because red-eared sliders produce little saliva and use the water to help swallow. A young slider's diet leans on a quality pellet and protein foods, with leafy greens offered even if they are ignored at first, since tastes broaden with age. Some owners feed in a separate small container to keep the main tank cleaner, which also lets you see exactly what was eaten during this watchful first week.
Wash your hands after handling the turtle or its water, every time, as a standing household rule, and keep the slider away from kitchen surfaces.
When a quiet slider needs a vet
Healthy settling still includes daily basking, bright open eyes, and a shell that feels firm. Contact a reptile veterinarian if your slider lists to one side while swimming, basks with its eyes swollen shut, blows bubbles or gasps at the surface, refuses all food beyond a week, or develops soft or discoloured patches on the shell. Tell the vet your water and basking temperatures, because those numbers shape what the vet looks for first.
The daily rhythm of filter checks, feeding, and lamp timing is exactly the sort of routine KinsLe Care Teams is built for, letting you assign each of your slider's jobs to a household member and see a timestamped record that it was actually done.