Tarantulas don't need much in the way of space. For burrowing or terrestrial spiders, the cage typically should be about three times the spider's leg span long and double the leg span wide.
2. Hermit Crabs
Although hermit crabs don't need a lot of space, don't be taken in by the shops that sell them in tiny plastic boxes. They need more room than that.
3. Mice
Mice are great for small spaces, particularly if you don't have much time to handle your animal but still want something cute, furry, and fun to watch.
4. Emperor Scorpions
Emperor scorpions are fine living in a 10-gallon tank, and they're definitely interesting to watch.
5. Frogs and Toads
There are several frogs and toads that are suitable for small spaces. Dwarf clawed frogs are very small and completely aquatic, and a gallon tank should suit them.
6. Hissing Cockroaches
If you live in a rental, your landlord might not be so keen on you keeping a cockroach as a pet (so check regulations).
7. Giant Millipedes
Giant African millipedes are definitely not traditional pets and might not be permitted where you live, but they are quite fascinating.
8. Hamsters
Hamsters need at least a 2-square-foot cage that has space for their food, chew toys, and a covered area in which they can hide and sleep.
9. Snakes
Among snakes, corn snakes are good for beginners and don't need huge homes to thrive. A 20-gallon tank that is fairly long and shallow should be fine for an adult.
10. Geckos
Leopard and house geckos are among the best choices for reptile pets, especially for beginners.