So I have googled this extensively, and the most popular things that seem to come up are parasites and lockjaw. I'm not entirely sure how to diagnose one or the other, but I did remove the clownfish and have a good look at her with a magnifying glass and couldn't really notice anything, but I did note that the gills seem a bit flared.
The tank has been up and running for over a year and the params test as follows.
No3 - 1 ppm (Elos)
Po4 - 0.04 ppm (Hanna)
Alk - 7.2 dkH (Hanna)
Ca - 420 ppm (Salifert)
Mg - 1400 ppm (Red Sea)
Salinity - 1.026
A recent addition would be 4 blue/green chromis.
I don't have ammonia and nitrite tests anymore as the system has been up for quite a while as mentioned above. I took some pics, they are terrible cell phone pics because my DSLR is currently charging but I could definitely get better pics later if so required.
This appears to have happened overnight, she's always a voracious eater and I came home from work today and fed the tank as per usual and she's just hanging near the anemone she hosts and watches the food float right by her when she's normally up near the top ready to steal as much as she can. Her mouth is open all the time and what food by chance gets in her mouth she doesn't seem like she can close it.
Here are some photos, any help at all would be greatly appreciated. The pics are clickable thumbnails!

I have a short video as well that I'll upload in the next comment, not quite sure how it turned out so I'm checking on that.
The tank has been up and running for over a year and the params test as follows.
No3 - 1 ppm (Elos)
Po4 - 0.04 ppm (Hanna)
Alk - 7.2 dkH (Hanna)
Ca - 420 ppm (Salifert)
Mg - 1400 ppm (Red Sea)
Salinity - 1.026
A recent addition would be 4 blue/green chromis.
I don't have ammonia and nitrite tests anymore as the system has been up for quite a while as mentioned above. I took some pics, they are terrible cell phone pics because my DSLR is currently charging but I could definitely get better pics later if so required.
This appears to have happened overnight, she's always a voracious eater and I came home from work today and fed the tank as per usual and she's just hanging near the anemone she hosts and watches the food float right by her when she's normally up near the top ready to steal as much as she can. Her mouth is open all the time and what food by chance gets in her mouth she doesn't seem like she can close it.
Here are some photos, any help at all would be greatly appreciated. The pics are clickable thumbnails!

I have a short video as well that I'll upload in the next comment, not quite sure how it turned out so I'm checking on that.