Clownfish lying on the bottom of my tank

[TheSWHobbyist]

So today when I got home from work I noticed that one of my two clownfish was lying on the bottom of my 75 gallon saltwater tank and it looked as if he was tired or struggling to breath. However now the clownfish is swimming faster than normal along the top of the tank just below the surface of the water. I read on another website that if the fish starts lying on the sand it could mean that my tank does not have enough oxygen in the water. I was just wondering what I should do in the case that my water is lacking oxygen and how I could test to see if this is the problem, or could this just be because I just recently bought them and maybe their stressed? What other things could be causing my fish to act like this and what could I do to help them?

I have a 75 gallon saltwater tank with 2 clownfish which I bought less than a week ago along with a shrimp. Additional information is that my water temperature is at about 76.5 degrees Celsius and the specific gravity is between 1.023-1.022. I would much appreciate it if you could help me out with my questions regarding my fish.

 

[Nanook]

[moved]

 

[Mrscribbled]

Unless you have absolutely no water movement I am doubtful its low oxygen. The shrimp would be dying most likely. Were the fish quarantined? I'm assuming not since you just bought them. Do you notice any sloughing of they skin? I'm guessing its brooklynella.

 

[DgenR8]

my water temperature is at about 76.5 degrees Celsius

That's 169.7 degrees Fahrenheit. If that were true, I just found your problem, your fish is cooked.
I think it's safe to assume that you meant to say 76.5* Fahrenheit. That temp is fine, wouldn't hurt things if it went up a bit, but it's okay where it is. Depending on how you read salinity, yours is fine for fish, a bit on the low side for corals/inverts (shrimp, clean up crew).
I think the issue may be found in what you're using to test the big three, Ammonia, Nitrite and nitrate, and what the test results are.

 

[MrTuskfish]

^^^^I agree^^^^^

Ammonia is seldom a problem with established tanks; but a real concern for newcomers. Also,as MrScribbled said, brooklynella is always a concern with clowns. His skin question will answer that. If the fish were't quarantined; anything dangerous in your LFS tanks is now in your display. I'd make a QT your next purchase, check Craigslist.