1. You should never add uncured live rock to the aquarium. Doing so can release harmful levels of ammonia into your aquarium.
2. Stingrays make wonderful pets for the aquarium, but make sure you can properly care for your stingray in your home aquarium.
3. Make sure you ask plenty of questions when you are buying accessories or fish for your aquarium. The salespeople are there to help you, and should be able to handle any concerns you have when buying items for your aquarium.