A wheel is useful, but enrichment can include much more. Hamsters naturally explore, dig, forage and create sheltered spaces, so the enclosure should offer varied opportunities for these behaviours.
Add depth and variety
Provide suitable bedding depth where possible, hideouts, tunnels and safe chew materials. Scatter small portions of appropriate food to encourage searching instead of placing everything in one bowl.
Check the wheel fit
The running surface should allow the hamster to run without an excessively curved back. Choose species-appropriate dimensions and inspect moving parts regularly.
For diet, illness or species-specific housing questions, consult a veterinarian experienced with small mammals.