Need help...Fish having trouble breathing...

I'm new to the hobby and got 3 blue green chromis three days ago. They were doing fine until this morning, and now they are hiding together and appear to be struggling to breathe. (Mouths and gills are moving rapidly) my husband had added water last night. I tested the parameters and all were fine but there were about 5 ppm of nitrates. The water temp was 78 but I have lowered it to 76. What is happening, and what can I do?

 

Nitrates are fine but was there any ammonia or nitrite? What's the salinity? Being that water was added and low salinity can cause rapid breathing. I'd get the temp up to 78-79, 76 is a bit low IMO. Are you running a skimmer? Low oxygen levels can cause problems as well. Also, what size tank do you have?

 

The ammonia and nitrites were both at zero. The salinity 1.024...Our temp was at 78, but someone told me to lower it because it allowed for the oxygen levels to be higher. We are not running a protein skimmer. We have a 55 gallon tank with an Aqueon 55 filter, and 2 hydor koralia 850 gph

 

Point one power head at the surface to increase agitation, that will promote gas exchange. Add an air stone with an air pump if you have one.

 

How long was the tank cycled prior to these fish?

That is correct info. There's nothing wrong with 76F.

 

I've had the tank for a little over a month, and we started with cured live rock. I was told to add fish food daily to cycle the tank. We did this for several weeks, with no spike in ammonia. I had talked and posted to several aquarists, some of which suggested the tank may have already been cycled. We added some hermit crabs, and now these fish. As to your question, I'm not sure about the cycling of the tank because it never made sense to me. I was told to add fish a little at a time to allow the good bacteria to increase slowly over time in case it hadn't fully cycled.

 

Yes and feed very LIGHTLY at first.It is still possible you have had some sort of mini cycle which may have burned the fishes gills.
The cycle never really ends.

 

What is your salinity or specific gravity? If the salt level is not right they may struggle to take in enough oxygen due to an imbalance is osmotic pressure.

 

What type and brand of test kits are you using? If the problem is neither low O2 or a cycling problem the fish could simply be stressed due to acclimation.If this is the case it would help to simply turn off your lighting and leave the tank alone for a while.

 

^^^^