Problem with Pajama cardinals

[Jesterrace]

I have a single captive bred PJ Cardinal in my tank who has done pretty well (although it tends to hide a bit during the day, since it is my smallest fish). I considered adding more, but after more research and observing them at my LFS, I decided against it. Just saw too many issues with fin nipping when they were kept together and was told that they would likely kill each other off if they were kept in more than a pair. Given that my tank is in a good grove with very little aggression right now (My Melanurus gets territorial with the Leopard at feeding time and occasionally my Coral Beauty will do a very brief "out of my way" charge at the PJ Cardinal, but that's it), I decided not to rock the boat, so to speak.

 

[Meggplant]

Hey guys.

So, I started with 7 pajama cardinals in a tank with a scopas tang, a royal gramma, several nassarius snails and a pom pom crab. I came home from work one morning and found a pile of snails in the middle of the sand. I immediately knew something had died. It was a PJ cardinal. The snails had already emptied his skin. I threw him out. A couple of days later, I noticed one of the remaining PJs being blown around in the flow of the tank. He was still very much alive though, and would straighten himself out briefly. Eventually, he became stuck against the weir of the overflow, pretty much lifeless in appearance, and not knowing what else to do, I removed him and flushed him. Today, I noticed the same behavior in yet another, and just now found him stuck to the overflow. They are all very active and healthy appearing, and eat like crazy. I thought maybe it was swim bladder, because even though they can't swim well when this happens, they appear to be in good health otherwise. Normal breathing rate and all. I feed thawed Mysis once a day from a medicine dropper.
All other inhabitants are doing great including the pom pom crab, and corals including acro. My parameters 10 minutes ago were:

Salinity 35PPM via refractometer
PH 8.2
Amonia 0
Nitrite 0
Nitrate 20 (Water change is tomorrow morning)
PO4 0 ish... I need a better low range tester
Ca 440
DKh 8
Mg 1300

Any help or previous experience would be greatly appreciated!

You flushed a partially alive saltwater fish? Why would you ever do that. It probably had an insanely slow painful death. You could have taken him out quarantined him and treated him or even euthanize him in a much more humane way. I know this post is old now but never flush another fish EVER again. Just dont do it.

 

[Sharir]

Hey guys, today I got a pair of pj cardinals. After a 15 minute drip acclimation I added them into my tank. My tank has a resident pair of clowns.i noticed that one of the pj cardinals was all floppy and listless, he even got stuck onto the overflow strainer. Is this normal or should I be concerned or is he just stressed