The color of Lava stone, also known as Basalt, is mainly dark. It is an intense mineral that forms when gasses in magma begin to solidify and harden into rock.
Producing a conducive environment to the aquarium inhabitants is the primary goal. Lava rocks will help to achieve this quickly and without the struggle. These rocks are covered all over the surface by holes and pores which act as the shelter to the beneficial bacteria known as denitrifying bacteria. This bacteria helps in maintaining the nitrogen cycle within the aquarium. They break nitrate to form oxygen and nitrogen offering a conducive environment for your fish to grow.