Large bubbles are released in a tube about 1 inch wide. As they rush upwards, they pull the water in the tube up as well. These freshwater fish include guppies, mollies, platies, and swordtails. These are rocks removed from the vicinity of a tropical coral reef with all of the life intact on them. They commonly have algae, sponges, worms, feather dusters, small crustaceans, polyps and urchins on them.
Live rocks are an important way to build up a complete and stable ecosystem for a coral reef.
These filters mechanically remove particles from the water. They require a special fixture and ballast . They are the closest thing we have to artificial sunlight, and are typically used on reefs and planted tanks. Do not confuse these with halogen bulbs, which have a very yellow light not appropriate for aquarium use. These are polyester pads which have been chemically treated to absorb certain substances from the water.