Help Me Convince Parents!

There's no reason any of those animals should smell as long as they're being maintained properly. I have had multiple fish tanks, multiple reptiles as well as a large colony of rats(one of the smellier rodents) all at the same time when I lived with my parents and smell was never an issue. I also had a job that fully supported my hobby at the time including paying a portion of the rent and utilities, my own food and all products that my animals needed.

If you want to convince your parents to let you get another animal first up your maintenance on the animals you already have till the smell is no longer an issue. Then see about getting working papers so you can get a job so at very least maybe you can cover any expenses your pets incur. Trust me heaters, lights, filters and water changes can wind up costing quite a bit for your parents never mind any food or other products they pay for so you can have pets. These all burdens that you may not realize your putting on your parents because you might think just feeding them and cleaning up after your pets is the only burdens associated with them. If you care about your pets and your parents think more about what you can do to get what you want instead of just asking your parents for more pets. Earn what you want and you'll find it's all the more rewarding and you'll appreciate what you do have more.