1. It is never a good idea to add shells from the beach into your aquarium. Introducing shells raw from the beach can add harmful bacteria and potentially new creatures to the aquarium.
2. When adding plants to the aquarium, be sure to check the lighting needs. Try to find plants that will fit the pre-existing lighting conditions of your aquarium. You should avoid plants that require much more light than the fish in your aquarium.
3. You should always purchase the correct lighting setup for your aquarium. Doing this will make the habitat much better for the fish and plants in your aquarium.