That all depends what you are trying to seal... Wood? Joins?
If you are sealing the joins, consider using a hot glue gun. The glue fills cracks nicely when it's hot, and dries to a plastic-like consistency that makes it easy to wipe down.
Whereas aquarium sealant (marine silicone) tends to become rubbery when dry, and starts to flake off after a while, and after repeated cleaning.