Murray,

We've only lost 5 fish total. I doubt its water quality, as our corals are thriving, clams are fully open. The gsp we got at the meet is thriving for the first time in two years (I'm so excited over this!).

I do have to say that I suspect it may be death by rabbitfish. They are poisonous and our rabbitfish is a bit, um twitchy, in that he is constantly flaring the moment anything moves in his line of sight.

We had, originally 13; LemonPeel Angel, Singapore Angel, two Tomato clowns, Ocellaris clown, regal tang, 4 chromis, fox face, two mandarins. All the fish that have died, LemonPeel, Singapore, large tomato, and both mandarins all frequented the rabbitfish's favorite areas to hide. The large Tomato was allow quite agressive when anyone approached the anemone.

Assuming it is a water quality issue, would I not see signs of something? None of the fish are breathing hard, nothing. They've all died sometime throughout the night, never lights on times. What illnesses attack at night? What type of symptoms should I be seeing?

Does anyone know what symptoms rabbitfish poision bring on? Or how long it takes to become fatal?

If the deaths happened after lights out, I suspect a nocturnal predator. But then you'd see wounds on the fish from the predation, or possibly some sort of slime covering part or all of the fish if water flow is not really high.

How big is the tank? 13 fish could be agression depending on tank size. I'm guessing something stessing them out at night as well. Or it could be a drop in O2 levels...just a guess though.

We have a lot of waterflow, and I'm not seeing any slim on any of the bodies. All the fish were/are quite small. The largest fish, is only about 2" in length, and that is the foxface.

I did note today that the foxface sleeps with its hackles? raised, and did exhibit some minor agression towards my tang todaay while feeding.

I'm still having no luck researching what kind of damage foxface posion does on other fish.

Does your skimmer run 24/7? Could be a drop in O2 levels particularly since it appears to be happening at night.

The skimmer does run 24/7, except for when its off for feedings. cleaning, etc.

What causes O2 to drop in the evening? Just the lack of water circulation?

My condolences man that really sucks. What are you feeding them? anything that might not be so fresh anymore? Do Foxfaces exude poison into the water as a self defence measure? possibly a power failure in the night that you didn't know about?

How are your inverts doing?

With all your corals doing great it really doesn't sound like a Water problem. I like the O2 theory.
You say everything looks normal and all fish are behaving normally before lights out?

One would think that inverts and corals would feel the effects of poor water or even water contamination before the fish.


J

Thats what I think......I run the Skimmer 24/7 and it's a big beckett skimmer so I don't really think it's an oxygen issue as nothing has changed really in the last 5 months, why would oxygen be a problem now...

My inverts are doing fine my anenome's(sp?) are both open and out, hermits seem to be really active(more so at night) my starfish are doing their thing, and the snails are doing a great job at keeping the glass clean!!!

We feed mysis, Nori, Formula 1 pellets, spirulina, Krill(for the anenome's)
all of which aren't that old!

If their was a power failure I would notice that all my clocks would have reset!!

Lots of algae/macroalgae will add lots of CO2 at night and O2 during the day.

Also, was doing some reading on isopods today related to an incident that happened to me last night.

Here are two articles on parasitic and scavenger isopods .....

http://reefkeeping.com/issues/2002-05/rs/index.php

http://reefkeeping.com/issues/2006-02/bp/index.php