hey lpenn31.. assuming its a 6X2X2 with 70 % water and the aro you are buying is about 5 inches.. it could def last for a year or two.. and the main thing is as it grows bigger.. its best to keep jus the aro in the tank.. if it is goin to be the same 125g in your tank setup with the existing tankmates.. that should be a different story.. and to your question.. legally i think you can own a silver/black or a jardini..or an african aro.. so these should do fine but totally depending on the size you buy em at..