INTRODUCTION OF FISH WHEN aquarium is fully planted and arranged, cover water surface with a sheet of paper before filling. This will prevent plants from coming loose and gravel being disturbed. Fill to upper frame, as the aquarium is most attractive when filled to capacity. A newly planted tank should stand for at least 3 days before fish are introduced. It is well, during this period, to leave the light on as much as possible so that plants may take root and the water adjust itself to the proper temperature for receiving fish. It is inadvisable to begin with a large collection of fish.