Indoor Bonsai Tree - Very Old Showcase Tiger
Indoor Bonsai Tree care is hard with most species. I would only recommend it with varieties of Ficus. As well as, Hawaiian Umbrella Tree (Schefflera). There are a few other species that can work inside. However, keep in mind trees live outside naturally. So ideally keeping your bonsai outside is best. A full spectrum plant light can solve the biggest issue, which is light. A fan is a good idea but do not keep your tree under drafts from air condition or anything like that. This is not good for your tree.
Tiger Bark Ficus Bonsai will thrive outside as well. You will always get more growth outside. Just be careful if temperatures drop below 40 degrees in your zone. Although, Ficus are very tough trees if it gets under freezing bring your bonsai tree inside to avoid shock.