A lot of dead fish, what went wrong?

[Eclectic Taste]

Okay, guys, I need some help. I have a 6 month old 75 gallon tank (mixed reef), 6x54 T5 lighting, 85 lbs live rock & 1-2 inch sand bed. In just one week I've had 4 confirmed dead, and 2 MIA presumed dead:

Dead: Bi-Color Angel, Majestic Angel, Flame Angel, Blue Tang
MIA: 1 Clown Fish, Royal Gramma
Survivors: Diamond goby, Clown fish

Prior to their deaths all fish were swimming actively, would eat like mad when fed, and spent all their time picking at the rocks and glass for pods & whatnot. I would go to bed and find a dead fish the next morning, stuck against the CL intake. Very distressing.

Parameters are great:

Ammonia - 0
Nitrite - 0
Nitrate - 0
Ph 8.2-8.4
Phosphate - 0
Calcium 400-420
Kh 8-9
Salinity 1.024
Temp 77-80
Makeup water is from RO/DI via autotop off, TDS is 001.

All tests done with fairly new (<6 mo) Aquarium Pharmaceticals test kits. I was having a little trouble with high temps (82-85) about 3 weeks ago, but since then I bought an air conditioner for my room and since then the temps have been averaging in the high 70s.

Other factors:
I run my lights from 5am to 3 pm to minimize heat gain.
My sump/overflow runs 24/7, and I have a lot of chaeto in there. Skimmer is an Octopus NW150, and I get good amount of gunk each week.
My closed loop pump is on a timer to run ~2 hours then off for 1 hour. I do this to minimize heat gain.

Other Livestock:
Various snails & hermit crabs,
Pink tip haitian anemone,
Torch coral,
Monti Cap,
Monti Digitata frags,
2 Oregon Tort frags,
Green acro colony,
Cat's Paw Coral,
Chili Coral,
Colt Coral,
2 colonies of Flower pots,
Favia type brain coral,
3 different Zoa colonies,
Hairy mushroom colony,
Mushrooms,
Tons of pink & green coraline algae on everything.

All the corals look really healthy, the tentacles on the softies and anemone extend very nicely, all the others extend polyps and have good color when the lights are on.

I am very frustrated at the sudden and inexplicable fish deaths, my wife is ready to make me sell the whole affair. I like corals, but seeing the fish swimming around the tank is what really makes the whole thing come alive for me. What could I be missing to cause sudden deaths at night?

 

[Doahh]

internal parasite maybe?

 

[shiveley]

if it's an over night occurence then maybe you're having Ph shift issues, or your oxygen saturation levels are low/dropping when the tank lights are off.

 

[mpoletti]

Did one die, then they all started to die, or did they die al once? The test kit you have--Is it the one that you add 5 drops and shake? If so, those test kits are not too acuurate.

 

[matttaylor]

I'd be more concerned with the closed loop turning on and off, especially at night. Your fish may be hiding near the intake, and when it comes on they are getting sucked into it. Leave it running all the time (heat shouldn't be an issue) or use eggcrate to make a better screen to prevent your fish from getting to close to it. I have some eggcrate you can have if you need it.

Matt

 

[kevin95695]

Wow. Sounds freaky. All your numbers sound good to this noob. You're finding bodies, so it doesn't sound like predation. I wonder if you had some kind of nudi die and toxify... Any clues on the bodies you're finding? Marks, bruises, abrasions, lesions, infections?

 

[Eclectic Taste]

The fish have died one at a time - they don't have any lesions, but they lose color an look pale. The test kits are the 5 drops & shake variety (API). I could get one or two Salifert kits, but which ones? Also, is there any way to test for toxicity? My hand doesn't sting when I put it in, no more so than whenever you rub salt on a scratch.

I'm going to leave the CL running 24/7, especially now since I have supplemental AC in the room. I wonder about Ph crashes & stuff, but how to determine it without a continuous Ph monitor? Should I leave the light on the refugium on 24/7? Would that affect the oxygen or Ph levels?

 

[matttaylor]

Leaving the fuge light on will help to maintain a constant PH as well as oxygen level. However in my opinion the real culprit is the on / off cycle of the closed loop. If the CL is off and flow is seriously reduced in the tank, oxygen depletion can happen rapidly, especially in a heavily stocked situation. I'm more inclined to believe that your fish died from simply being in the wrong place at the wrong time when the CL turned back on.

 

[mpoletti]

I would do two 20% water changes. One today and one on Sunday. That will dissapate the toxins in the water.

Those test kits are no bueno. I really like the elos kits. I had the salifert kits and they served their purpose. I always test for alk and nitrate once a week.

 

[Eclectic Taste]

I haven't measured ph at night vs. daytime, but I will tonight.

None of the fish were qt'ed (my bad), but they were bought from different dealers, all with good reputations in the Sacramento area. I know the majestic had been in the store for at least 1 month, because that's when I first saw it. I didn't buy it until much later because I didn't know if I could keep it in a 75, but when I had done a little research on it and it was still available later, I bought it. I assume it was the same fish, it was in the same tank!

Since I'm going on vacation in August, I think I'm just going to do a few water changes over the next few days/weeks, and won't add anything until I return. Then when I get back I can think about restocking slowly, no more than 1 fish per 2-3 weeks. Maybe I can talk the wife into letting me set up a QT tank, but I have no place to put one.

 

[mpoletti]

You should be fine. I know my tank did some wierd things between 5-9 months. If I remember correctly, I lost a couple a fish during that time. I would do the water changes and start back slowly. IMO, a tank that is 75g is too small for that many angels. Once the battle starts, it will end up in your sorrow.

Make a list of what fish you really want in your reef. The blue tang is a touchy fish to get acclimated into a new system. If that is the tang you want, I would concentrate on that. Let him have the reign of the tank and get comfortable.

 

[Eclectic Taste]

Thanks, I will definitely take it slow when i return. I don't think it was fighting that killed the fish, because there were many, many times they would be swimming next to each other, picking on the rocks side by side, not even chasing each other.

Would it be okay to add any corals at this time, or should I just wait?

 

[mcurl98]

IMO- if it were something we could test for, it would be ammonia or nitrite. IME most brands of test kits get these basic measurements right. While I use Salifert, I have also used AP for these two measurements and they have always matched. The nitrate kits can be off a bit but your nitrates would have to be pretty high to kill fish. Seeing that your corals and anemone are fine, I don't think it could be nitrates. Your PH is fine and the night time swings would not hurt anything. The fish can handle large PH swings with no problems. I am assuming you are saying the fish look great when you go to bed or when the lights go off-that they only become pale after they die (which is normal)- if so, my guess would be the on and off of the CL.

 

[yoboyjdizz]

double post

 

[yoboyjdizz]

Did you ever witness one of your fish dying? What was your flow like? You say you turn your pump off here and there i would let it run. In six months that seems like a lot of fish and could of been oxygen problems. Happen to me in my old 72 i added alot of fish first few months and my levels seemed fine but were using that could of test kits. (not i only use salifert and probes ) but my fish were just swimming fine and then bam dead.. I did witness one death with an angel seemed like it was breathing rapidly then bam dead. Only thing i could come up with was to much to soon not enough flow and oxygen for the fish.. This hapen to all my fish in a matter of a week. The only surviver was a yellow tang. There is a disease though that kills fish over night forget what its called.

 

[Eclectic Taste]

I did notice the bicolor angel was hiding out in the corner a day or two before he died, but he was still swimming, not laying on the sand or anything. I found him dead in the corner opposite from the intake, but I guess bicolors are a less hardy species, so a newbie tank may be the fault.

 

[Reefugee]

Just my opinion: Based on your description, you probably have some toxin in the tank that you don't know about. This could have been introduced by a coral, accidental spill in the tank, or contamination on your hand. Unfortunately, without knowing what is causing it, you can't easily test for it. I would recommend a lot of water changes to try to dilute the toxin as much as possible.

I had an incident where all my corals and fish were acting weird. I could figure it out since all my water parameter looked good. It finally turned out to be a deodorize that one of my girls were spraying, and some minute amount must have gotten into the tank. Only way to fix it was frequent and large water changes.

Minh