Aquatic vs normal silicone?

Check the label on the silicone you used and check to make sure there is nothing in it to kill mildew or bacteria. These chemicals will have a negative effect on your tank inhabitants and possibly kill them. Usually anything for bathroom or kitchen is not good. Silicone made for window/door is sometimes safe. I believe GE Silicone 1 is commonly used for different aquarium applications, it is also the same stuff you find in the silicone tubes at your local fish store.