Tiger barb pecking order

[domingo3]

Hi. I bought 7 tiny tiger barbs about 2 1/2 weeks ago. The one of them that was lowest in the pecking order started hiding in the plants and not eating very much, and has since disappeared. Now I have 6 left. Four of them are growing, and there's another two that are now mostly hiding out in the plants. One of them in particular seems to stay hiding even at feeding time, and will only eat towards the end of feeding time. The two are smaller than the others.
Is this just the natural order of things or is something wrong? The tank is fully cycled and I don't see any signs of disease (although I am an amateur). The water tests very good at 0 ammonia, 0 nitrites and <5 ppm nitrates. Any ideas?

Thanks

[Lady Hobbs]

I hate it when one fish seems to take all the bullying and must spend his life in hiding. They're trapped in a glass box with no where to go and always seems so unfair to me they must live like this. Hopefully he will grow up quickly and come out kicking but most likely will just be tormented, stay small and end up killed. Perhaps you can trade him in for a female?

[Brhino]

My smallest danio does this. He hasn't eaten, from what I can tell, for weeks. He has no belly to speak of. He spends most of his time hiding. At feeding time he either hides, or swims through the cloud of food particles without eating. Every day I'm surprised he's still alive.