Do you mean that the tentacles are elongated and not bubbled?
If so, there are many factors that cause this. It is not always a sign of bad health.
~Michael
Lighting, water flow, feeding habits, water parameters.
From what I have read, and from my experience they tend to loose the bubble tips under lower lighting. The brighter the light the more bulbous the tips are. Also when they get hungry they will stretch their tentacles.
~Michael
That makes sense to me. if you look at my avatar. thats a GBTA under PC lighting(130watts) in a 30 gallon.(this was before i knew better) since then it has been under the MH of my new tank it has clearish bright green very bubbly tentacles.