Yes! You can use an aquarium for and indoor herb garden! Just be sure to clean it very well, make sure there are no cracks-seal them with clear weatherproof tape or sealant apoxy. Then layer the bottom with 1 inch of leftover aquarium rock(make sure they are clean)-or just purchase more, then 1 inch of charcoal chips-this will be your drainage for your plants. Then add 5 Inches of potting soil-mix in some organic food for veggies. Then add your herbs-spreading out about 4-6 inches from each other. cover with remaining soil and water regularly for first couple of weeks-do not over-water though. You can stick your finger in the soil, if it's damp-don't water. Set in plenty of sunlight on your patio. Enjoy herbs whenever you want them! you can always change out the herbs too!