Bamboo shrimp are filter-feeders, right? If so, they prefer not to have to pick at their food. It damages their feelers. In fact, if you see them picking at food, rather than perching in the current and waving their arms around, that means that they're not getting enough food.
That being said, you can feed your fish some nori (they'll love it too), which will introduce some nitrogen, phosphorous, and vitamins and minerals to the tank, which will fuel algae growth, which will keep the bamboo shrimp happy and healthy. Just don't overdo it.
