The all-in-one nano aquariums are chalk full of limitations right out of the box. More often than not, their lighting and filtration are both inadequate, and their lack of flow usually requires the addition of additional powerheads. That said, these systems are incredibly popular amongst new and seasoned aquarists alike. For the new hobbyist, the tank represents an inexpensive experiment that can determine if they are truly interested in sticking with the hobby. Experienced aquarists take advantage of these systems by setting up species specific tanks for small fish that would otherwise get lost in the big reef tank. Either way, if you find yourself with a nano that doesn’t perform up to your standards, the big name AIO tanks can be easily modified and there are tons of aftermarket add-ons that can be used to improve filtration, lighting, and flow.