2 dead, 1 missing help!

I left for work this morning and everything was fine. I came home to 2 Kaudern's Cardinals in the sand and one MIA. All other fish/corals/inverts doing fine and breathing normal. Cardinals were in the system for about a year.

Other inhabitants:
Coral beauty
Purple pseudo
Kole tang
2 Perc. Clowns
Had 4 Kaudern's. Now I can only find one!

Coral banded shrimp
2 Blue legged hermits
Nas/nerite/cerith/turbo snails

Acans
Ricordea mushroom
Blue mushroom
Neon green nepthea
Pulsing Xenia *JUST ADDED FRIDAY*

System:
125 gallon with 30 gal sump
Up and running for 14 months
Last water change 20 gallons 2 weeks ago
3400 gph total flow
Started with 120 lbs dry rock 20 lbs live rock and 2 inches live sand
11 hr light cycle with LEDs
Feed 1 cube of mysis daily in evening. A few pellets in the afternoon when I get home from work. And 2x2 sheet of nori for the tang daily.

Water:
77.9 degrees
1.024 SG
Ammonia zero
Nitrates 2 ppm
Ph 8.2
Red Sea test kits

 

Quiet a puzzle. I'm guessing nothing new has been recently introduced?

 

they are known to fight - could have been mutual aggression as they matured

 

Update:
Still haven't seen the other Cardinal. He is dead I presume. The last living Cardinal is eating and doing just fine. Normal breathing and looks healthy.

The last thing that went in was the Pulsing Xenia last Friday.

I looked the bodies of the 2 I pulled out over real good. Fins all in tact, no spots, nothing... Really strange to lose 3 in 12 hours without a trace. Everyone got along really well. The smallest one is the only one I have left.

 

Marine velvet may be a possibility, it is not easy to identify early on and you have an uphill battle to save any fish if that is what is in the tank, it can hitchhike on corals.

Marine Velvet (MV) has been making it's rounds, I lost 4 fish in a matter of days (all smaller fish), the only fix was netting all of the fish and putting them in a hospital tank with meds for two months to let MV run it's cycle in the main tank.

You have to act fast if it is MV, it is the quickest killer I have seen in 25 years of fish keeping.

 

This is probably unrelated, but don't Kaudern's usually only live a year in captivity?

 

Anyone know if there is any merit to Marshall's statement? I hope not. Seems kinda reckless from a conservation standpoint. Mine were tank-bred BTW.

 

Not sure why you feel it was reckless, but was searching for some reason for the unexplained deaths. I did some more research, and I was not far off. Females seem to only live about 2 years, males 4-5. These are not long lived like most fish in the hobby.