Generally, it's recommended to adopt a guinea pig that is around three months old. At this age, they are typically weaned, their bodies are healthier and more robust, and they can eat solid food independently. Their physical characteristics are more apparent and easier to distinguish, while still having room to grow.

The reason for this recommendation is that younger guinea pigs are more susceptible to illnesses due to their weaker immune systems. They also tend to be very vocal when separated from their group. Guinea pigs younger than three months old are usually not yet fully weaned, making them difficult to care for privately. On the other hand, older guinea pigs may have hidden health issues, which are difficult for the buyer to identify. Also, adopting older guinea pigs might lessen the experience of raising them from a younger age.
Guinea Pig Care Guidelines
Here are some essential care guidelines to ensure your guinea pig thrives:
1. Environment
Guinea pigs have sensitive hearing and are easily startled. Therefore, their environment should be kept quiet, ideally with noise levels below 50 decibels. The ideal temperature range for guinea pigs is between 20-24°C (68-75°F), and they can tolerate temperatures between 18-26°C (64-79°F). Temperatures outside this range, especially higher temperatures, can cause miscarriages in females and harm the overall health of the guinea pig. These animals are particularly sensitive, so temperature control is crucial to maintain their well-being. Fluctuations in temperature can significantly weaken their immunity and increase the risk of disease. The ammonia concentration in their environment should be below 20mg/L, with an airflow speed of 10-25cm/s. High ammonia levels are associated with increased pneumonia rates in guinea pigs.
2. Diet
Avoid feeding guinea pigs foods like onions, garlic, ginger, chocolate, and coffee. Guinea pigs have a high fiber requirement, so ensure their diet includes balanced nutrition. Provide them with grain-mixed fruit pellets or guinea pig-specific food. A lack of fiber can lead to severe hair loss and fur-eating behavior. Guinea pigs cannot produce vitamin C on their own, so their diet must include vitamin C-rich fruits and supplements.