i actually have the same problem look at my pictures on my profile there are two really nice ones then i have a very short fat one thats like 3 inches tall but very healthy just wont grow tall for some reason????
Well it's hard to tell by just looking at a pic. But they do look pretty healthy for the most part.
If they're grown from seed, it's not uncommon to have a 'runt' plant that just lacks the vigor and health of the others. As long as the other ones seem to be healthy and growing fine, then things should be ok, and the problem is with the plant itself, and not necessarily something you're doing.
In one of the pics it says something about surviving a fruit fly attack. I'd be willing to be that those were fungus gnats, not fruit flies. But again, there's only so much you can tell by seeing a photo without more description.