Without any leaves, your poor plant looks a lot closer to "dead" than "dying." But don't bury it quite yet - with a little knowledge and a little work, you might be able to save it.
First thing to know is this is not a bamboo! This is a type of dracaena, a relative of the corn plant, called a sanderiana. Second, it is not a water plant! Some years ago, some growers got the bright idea of marketing sanderiana cuttings rooted in water under the name Lucky Bamboo. They are among the few types of plants that can stay rooted in water for years, but they're not really water plants.
So the first thing to do if you have a lucky bamboo that you want to keep, is to take it out of the pebbles and water, and plant it into soil. Use a fairly small pot, not much bigger than the amount of roots you have, and use a fast-draining, coarse soil; cactus
soil is acceptable, or mix up your own coarse soil.
Now, since your plant has lost all its leaves, if it's to live, it's going to have to make new ones. Pushing enough energy all the way to the top of that stalk to make leaves is going to be next to impossible, so you need to cut back the stem. I would cut it into 2 or 3 pieces, the first about 2" above the roots, the rest of the pieces around 3" long. Plant the piece with roots carefully into the soil, then stick the other pieces about 1"into the soil. Keep the soil slightly damp, and be patient. If there's any life in the stem pieces, you'll eventually get new leaves.
You might want to do some research on rooting cuttings. Good luck.