Its the rock, sand, gravel, whatever on the bottom of an aquarium.
because the fish want it
I have a 120 Gallon aquarium with sand. They love it.
a terrarium empty.
sedimentation
Yes ofcourse you can have them in your saltwater aquarium. You have to provide some space in your tank with good sand and feeding sand dollars is easy, for they mostly eat suspended organic matters and other fish wastes.
Sand Masters - 2011 Aquarium of the Pacific 1-12 was released on: USA: 21 August 2011
yes you can
No because the sand will make the water dirty, small rocks are usually the best.
Yes, but be prepared for some cloudy water.
gravel rocks sand peebles water
All you need is an aquarium, a filter, a lighting system, sand, live rocks, some saltwater, and something to start the cycle.