Epic failure and looming mass casulty...


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Ok so heres the set up. 93 gallon drilled cube, 40 gallon cube sump, with hang on inside fuge, bubble magus 150 skimmer, mag 24 return, live rock and live rock rubble in sump, 90# live rock in dt, 20# dry rock in dt, premium black sand substrate, 2 1400 gph power heads and a 750 gph power head, coralife 150 metal halide 3' fixture with 2 blue actinic power compact bulbs and 2 blue leds (night lights I assume?)
Live stock, (yes I know a couple of the tangs will get too big for my tank within time but my gpa has a 600 gallon system in his basement that I will transplant them to when they get too big for my system) hippo tang 2" long, sailfin tang 2.5"long, yellow tang 2.5" long, lemon butterfly same size as tangs, pair of black ocellarus clowns, diamond goby, lm blenny, cleaner shrimp, cleaner wrasse, purple dottyback (psuedochromis), about 30 snails and 45 mini crabs. Green button polyps, a big toadstool (leather?), blue shrooms and orange shrooms, colt coral, some type of anemone.... think thats it.
I had to leave town for 3 days for a death in the family (in virginia) so my ex fiance volunteered to keep an eye on my tank and feed them and cycle lights for me since I bought timers but have been too busy to set them up. When I had my 75 gallon reef she was into reefing right along beside me, so I felt confident that she would be able to keep it going with no issues. I had not had a death in this tank since I introduced all of the fish after 10 week qt.
Well when I was away my float valve on my ato failed and (stuck up/off) and my tank evaporation caused my salinity to go from the steady 1.024-1.025 to 1.028. So once I got home I checked my salinity first thing once I noticed that the sump was really low... and I had some water made up so I threw a heater in it and once it heated up I added 2.5 gallons and then checked again and added another 2.5 gallons to bring it down to 1.0265 (over a 4 hour period)
In that time while cleaning the glass I noticed the dotty back floating by my overflow and removed her... then I noticed that my lemon butterfly was not around and neither were my clowns... looking I found one of my clowns behind my rock work on the substate dead. I could not get to this clown without ripping rocks apart which I am going to do tomorrow... But I can not find the other clown or the butterfly... by this time it was time for me to go to work and it was weighing pretty heavily on my mind all evening at work. The clowns were by far my favorite fish in the entire set up.
When I got home tonight I started making more water and I am going to do a 20% water change tomorrow and try to locate and remove all of the deceased fish. I also noticed that the cleaner wrasse was not around when I fed tonight. So now I am thinking I may have lost him too.
My parameters are heat 78, ammonia-0, nitrate-0, nitrite-0, ph-7.8, alk-9.0, cal-420, mag-1250.
My latest additions to the tank are the toadstool and the anemone... which I dipped in coral rx, I am starting to wonder if the salinity did my fish in... or if maybe one of the 2 new additions is releasing some type of toxin... the remaining fish and inverts look happy and are eating fine.... any ideas? This has me almost to the point of netting these fish and taking them to my gpa to put in his qt.. and just tearing mine down. I love my fish and my set up... but this problem is reallly eating at me. Any help would be greatly appreciated. What I dont want is brow beating over the tangs...I stated my reasoning above as to why I have them temporarily in my tank.

Bummed reefer (feeling like a complete noob and Ive had a reef tank for the last 3 years...not long but at least im not brand new)

First thing in the am I am thinking I should net all of my inhabitiants and put them in my qts again... do you guys think thats a good idea?


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I don't see any advantage to move them know. You might have brought the sg downtoo fast. Bummer all around... Sorry for your losses.


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Thanks sly. Yea this is by far the worst failure/loss I've ever had...since my ex wife put a alligator gar in my 90 gallon tank full of angel fish with 3 discus. That sucked.. I am more upset about this one tho:(


New member
What do you use to measure salinity ? I am surprised that 1.028 was a fish-killer, would have thought that it was survivable.

You mention that your ATO stuck "off" and your sump was low, yet you also mentioned that you added "made-up" water...was that made up sea water ?...if so, I think you should have been adding RODI water only at first, to get your salinity down. Adding sea-water to a high salinity will not move it down much.

Maybe you have had overfeeding or such...but your params (nitrate, nitrite, ammonia) dont seem to suggest this.

Could some pollutant have got in there some way...soap on hands (or hand cream or some such)...maybe glass cleaner or fly spray ?

Seems a bit off to me that you lost the tough fish yet your Tangs survived...these are usually among the first casulties. Either way, its a lot of pain to have a good set-up go bad for whatever reason...but get back on the horse and persevere.
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I think the issue was the the 1.028 specific gravity didn't kill the fish, but his adjusting the specific gravity down too quickly was what killed the fish. Lowering specific gravity too quickly can definitely stress and kill fish.

Dr Colliebreath

New member
The dottyback and clowns are relatively hardy fish. Nothing jumps out at me but I doubt the salinity change was the killer. It went up slowly and not really too far, so that should have been manageable. The drop from 1.028 to 1.0265 was not too much or too fast, so that isn't the problem.

I would be looking for something else, either your recent additions or some pollutant. Try running carbon in case there is anything in the water that it can remove.


New member
Even double that change in salinity in half that time shouldn't have killed those fish. Even corals or invertebrates (maybe some starfish) shouldn't die from that, and they'd usually be the ones to go before the fish.

The Toadstool isn't a likely culprit either.
The Anenome...is this the one in the other thread that was figured to possibly be a Condy? It'd probably eat the fish rather then randomly killing them. Unless maybe it tried to eat a couple of them and they got away, and then died.

Otherwise, don't see any obvious reasons there for that amount of death.


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Now the anem eating fish I didn't think about but is highly possible. Maybe I'll rehome it. I pulled almost all of my rock out and only recovered the one dead clown. No sign of the butterfly or the other clown at all... idk? Salinity is checked with a cheapo refractometer and a hydrometer just to make sure. Reading 1.0245 now. I did a water change of 10 gallons and leveled out the salinity with the new water that was mixed and heated for 24 hours.
I did find the wrasse alive and well. Everything else seems to be thriving...that's what kills me about the losses I did have.