I think I weighed in on the other thread. It's always best to stick with the same thread, I may end up covering the same ground here.
This clown is breathing fast, I ran a few counts from the video and tried to average them, all were above 150 gill beats per minute, and one group was at 180 BPM. Normal clownfish should be under 120 BPM, and not so labored as this.
Here is some text I wrote about rates:
Aquarists are warned throughout this book that rapid breathing in their fish as a symptom of potential problems, yet few know just what “rapid” is. Obviously, fish kept in warmer water or those with gill disease will respire more rapidly. Actively swimming fish respire faster than sedentary ones. Less obvious is that larger fish respire more slowly and, in some cases, high ammonia levels will cause a fish to respire more slowly than normal. While there is some difference between species, (Chinese algae eaters will breathe twice as fast as any other fish their size) most tropical fish of the size kept in smaller aquariums should breathe at a rate of between 70 and 120 gill beats per minute. Relative respiration rate is the most important value – capturing the respiration rate of your fish when they are known to be healthy, gives you a baseline to compare to if you later suspect a problem. Not having this baseline data is an issue for newly acquired fish, so using the information below may serve as a secondary reference.
Fish may exhibit a variety of respiration forms in addition to the actual rate itself:
Rapid mouth open respiration – may be a sign of gill disease or toxic compounds in the water.
Rapid, shallow respiration – may be signs as above, or just a result of high activity level.
Rapid, deep respiration - possible chronic gill disease or anemia.
Coughing – a result of high levels of particulates in the water, or gill parasites.
Gasping at surface – usually seen in freshwater fish under low oxygen conditions. Marine fish will usually not show this symptom, even if they have respiratory issues.
Facing into water flow – This is how marine fish often respond to respiratory issues.
Slow, deep respiration – may be normal, or a sign of ammonia toxicity.
Slow, shallow respiration – normal for most fishes.
Jay