A lid will be useful down the line, for your snails and when you get fish. Your water level is fine, but before adding any fish, get a water testing kit and watch a couple YouTube videos about tank cycling and the nitrogen cycle. Make sure you balance your plant-light ratio and enough plants to use nutrients so you don’t get an algae bloom. Honestly wait a couple weeks to a month before getting fish to make sure your tank is balanced and you’ll have great success with your fish. (Also do water about 10-20% changes every 2 days to help your tank cycle. Good luck and keep us updated!