It looks to me that your lucky bamboo is root bound.
What that means is that the roots have outgrown the pot the plant is in and are getting suffocated.
This reduces their ability to take in fertilizers and water, even if you're feeding them on schedule and can cause stunted growth and sometimes, yellowing.
In a plant potted in soil, you'd see something like the second picture in this answer .
Your's looks a little different from that because of the pebbles, which are harder for the roots to push around.
But the problem is the same.
I would suggest getting a larger pot and transplanting it so that the roots get some 'breathing space'.
You might also want to propagate a couple of cuttings, as Mike Perry notes in this answer Before transplanting into a larger pot, I would take a cutting or two from the plant (if it's viable, I can't tell from the photo as it doesn't show the top/whole of the plant) and propagate those cuttings, just in case something goes wrong during the transplant process.
Here is a video on "
How To Propagate Your Lucky Bamboo" that may prove helpful/useful.
gardening.stackexchange.com/users/109/Lorem Ipsum
I've seen symptoms like this when the water has dropped too low (roots start to die and rot) and/or when the water has turned anoxic (no oxygen).
Note that rotting roots when re-submerged will quickly turn the water anoxic.
I consider my answer and yoda's above to have a lot of overlap.
We're both talking about a root problem and some variation of suffocation/anoxia.
One symptom of chemical anoxia is a sulfurous smell - and I have smelt this with lucky bamboo in an extreme case (stems had truly rotted!)
gardening.stackexchange.com/users/69/winwaed
Here's what we eventually did to save the plant, mostly following the answers: Removed the dead leaves and cut the dead parts off of other leaves.
Pruned the roots, and cleaned the green goo.
This is pretty easy by washing the roots under a faucet.
Changed the pebble, because it was covered with green goo.
We use potting soil instead of the pebble it came in
(I think they sell them with pebble just because it looks nicer).
Moved the plant to a bigger, opaque pot
(I think a clear pot and sun exposure allowed the green goo to grow on the roots) Propagated a cuttings.
The next generation is not doing as well as the parent.
Added plant stakes, because they both had trouble supporting themselves, and started having odd shapes.
We prune the roots and change the potting soil periodically.
We forgot to do it for a while and the cutting was sad, but it's doing better now.
gardening.stackexchange.com/users/225/Kobi
I had this happen to me once and eventually the yellowing went all the way down to the roots and the plant died.
After doing some research, I was told it was a fungal disease.
According to this FAQ, it looks like it could be a variety of things.
Edit
11/22/15: The original link provided above is no longer available, therefore I deleted it.
Although I'm not sure it was the exact reference, here is a Frequently Asked Questions page about lucky bamboo care from the same site.
gardening.stackexchange.com/users/798/Kyle Hayes
Mine was turning yellow until I stopped with tap water and started only giving it filtered or distilled water.
gardening.stackexchange.com/users/30358/Erica
You need do change the water it is so dirty the bacteri and fungi is killing the bamboo.
If you change the water weekly the bamboo will get healthier
gardening.stackexchange.com/users/24235/Eric woodring
Our lucky bamboo has turned yellow in a very short time, after we've had it for almost 2 years. We've trimmed all yellow leaves, and changed the pebble to clean the green algae - what else can be done? Why did this happen and what can we do to save it?
Why has our lucky bamboo turned yellow?
gardening.stackexchange.com
<diagnosis><houseplants><plant-health><lucky-bamboo>
gardening.stackexchange.com/questions/2937
gardening.stackexchange.com/users/225/Kobi
It looks like the roots are too big for the pot. You could also try watering it more and changing to non tap water. Your lucky bamboo may be root bound, meaning that the roots have outgrown the pot the plant is in and are getting suffocated. The water may have dropped too low or may have turned anoxic (no oxygen). You need do change the water it is so dirty the bacteri and fungi is killing the bamboo.
Your lucky bamboo may be root bound, meaning that the roots have outgrown the pot the plant is in and are getting suffocated. The water may have dropped too low or may have turned anoxic (no oxygen). You need do change the water it is so dirty the bacteri and fungi is killing the bamboo.