Gradinita: Well, an aquarium tank could be hard to maintain, especially that it is not the nature planted tank. One key reason behind is that the nature ecological cycle has to be working behind the scene to achieve a self-balance (or at least close to self-balance) of a tank. Live aquarium plants are crucial for this cycle as they are there to remove the nitrate from the water.

I used to have bare tank with fish, and plastic plants. The water smell is awful, and the algae problem keep coming back even though I changed water very frequently (and that contribute to the problem as well).

Hope it helps. Any experts out there to share your view? My limited knowledge is always proven to be inadequate in this great hobby.