URGENT HELP...all my fish died overnight and I have no explanation PLEASE HELP!

[davy31]

Hi, I woke up to the worst morning ever. All my fish in my nano reef died. 3 were on the sand bed and two were stuck to the sides of the flowheads. It was stocked with

3 - Ocellaris
1 - Blue Chromis
1 - Damsel

There are soft corals and inverts which seem ok. The parameters were all fine -

Ammonio - 0
Nitrate - 0 (I have been dosing nitrate and phosphate as my softies were shrivelling up.
Phos - 0.03
Ph - 7.8
Salinity. - 1.024
Alk - 11
Temp - 24 C

There have been. no electrical failures in the tank. The intank skimmer was shut off over night , this was done the last 2 nights in a row. I battled a a slimy gooey bacterial bloom last week and did a 50% water change and cleaned my filter material. It was really bad and I have a few previous posts about this problem. However the tank has been cleaned from the slime for the most part. I fed the fish brine shrimp yesterday around 3 times to help with increasing the nitrates.

I dose nitrates and phosphates to help the softies. In addition I dose a coralline algae starter by Microbe Lift. All my dosing is by microbe lift. The aquarium is about 8 months old and the fish seemed healthy and fine lasz evening when I fed them. They did not look stressed or oxygen deprived.

Something went horribly wrong...and I just feel utterly helpless and a horrid feeling like I killed my own fish. I am just lost for any explanations. Please help!

 

[ShadowMan]

Really sorry for your loss :'(
I've lost one fish in the past and that was bad enough, so can only imagine how you're feeling today!

What are your parameters like today? Any major spikes or drops?

 

[davy31]

Really sorry for your loss :'(
I've lost one fish in the past and that was bad enough, so can only imagine how you're feeling today!

What are your parameters like today? Any major spikes or drops?

Thanks, no the parameters are the same as I mentioned. Infact I tested last night before I went to bed and then I wake up to a dang death house. I tested the water now and they are the same. I also dosed a bit of nitrate and phosphate last night after the test but the results for nitrate are 0 and phos is 0.03.

 

[Clownfish2]

I would think it’s possible oxygenation decreased significantly overnight due to the skimmer being off. Bacteria plumes can also reduce oxygen levels.

I would also cross check my salinity checker with a different one. Maybe the salinity checker is giving you an inaccurate reading.

I would also rule out stray voltage from heaters, power heads, and return pumps.

For alkalinity, I’d aim for 7 to 9.

 

[ying yang]

My initial thought is low 02 for all fish to die at same time.
Skimmer offline so not helping with gas exchange.
Dont know all your power head placements but can see one just below half way mark in your tank and not near surface pointing upwards to help in gas exchange.
As nature wants to have equilebrium and get co2 out and 02 from air inside your tank but needs a little help with surface agitation so if not got enough surface agitation from skimmers/ power heads or air stones this can become big problem.
Maybe go to your lfs and buy a 02 test kit.which test kit is most reliable idk sorry as never used one.
But parasites is hard to believe would kill all fish same time.
Inverts and corals you say seem fine so that would rule out parameters being severley out of whack.
You had few bacterial blooms you say so they can strip oxygen out the water,not sure if this still happening ( is your water cloudy ?)
Big pest like bobbit worm i doubt kill all fish same time.
Just thinking all possibilities but still going back to lack of 02 in my head.
Sorry for your fishy friends lost but dont give up,just try your best to find out what could of caused this and learn from it.
Did see you say washed all filter material, ovbiously you didnt rinse/ clean it in tap water did you ? As tap water got chlorine/ chlorimine that kills the bacteria and makes it safe for us to drink but also kills bacteria in filters/ rocks/sand etc .
Hope you get to bottom off it

 

[Ryde]

+1 low 02

 

[davy31]

My initial thought is low 02 for all fish to die at same time.
Skimmer offline so not helping with gas exchange.
Dont know all your power head placements but can see one just below half way mark in your tank and not near surface pointing upwards to help in gas exchange.
As nature wants to have equilebrium and get co2 out and 02 from air inside your tank but needs a little help with surface agitation so if not got enough surface agitation from skimmers/ power heads or air stones this can become big problem.
Maybe go to your lfs and buy a 02 test kit.which test kit is most reliable idk sorry as never used one.
But parasites is hard to believe would kill all fish same time.
Inverts and corals you say seem fine so that would rule out parameters being severley out of whack.
You had few bacterial blooms you say so they can strip oxygen out the water,not sure if this still happening ( is your water cloudy ?)
Big pest like bobbit worm i doubt kill all fish same time.
Just thinking all possibilities but still going back to lack of 02 in my head.
Sorry for your fishy friends lost but dont give up,just try your best to find out what could of caused this and learn from it.
Did see you say washed all filter material, ovbiously you didnt rinse/ clean it in tap water did you ? As tap water got chlorine/ chlorimine that kills the bacteria and makes it safe for us to drink but also kills bacteria in filters/ rocks/sand etc .
Hope you get to bottom off it

Thanks, nope no tap water. Its all RO/DI. The skimmer is on during the day. I did however leave the door open close to the balcony last night and the ambient temp may have been around 15C. A am not sure if a temp change can cause this. But even then, the heater was on and its not the first time the door was open at night.

The parameters were fine, with oxygenation I assume since the skimmer is on during the day and off during the night this should not be a prob right? I also did a 30% water change to fight off a nasty bloom a week ago but the fish seemed to settle down in a day or two after the cleaning and changes. The flow is in the bottom third of the tank arrnaged to give a circular flow.

 

[ying yang]

My understanding of saltwater is it has capacity to hold less 02 than fresh water and saltwater fishes are used to more flow on the reefs than freshwater and 02 levels if not getting replaced ( like if water surface calm and no agitation) then the fish can use it up rather quickly)
Having heater in tank i would if thought wouldnt be a problem if kept outside door open aslong as heater was strong enough but will tag a few people who helped me lots @Mibu @vetteguy53081 @Jay Hemdal and see there opinion.

I see only 5 smallish fish but surface area of your tank not massive as only a nano and if no surface agitation then still think 02 could get depleted fast but lets see what these 3 guys and gal say

 

[ShadowMan]

I agree that low O2 is your most likely cause, especially if you've been battling a Bacterial Bloom, as those bacteria will be using up a lot more O2 in the evening rather than daytime.

Also as @ying yang suggested, it's definitely good to get some surface agitation to help expedite the gas exchange and aeration.

 

[vetteguy53081]

Some possibilities:
Stray voltage
Tank too new and ammonia spikes
False test readings
Ph a little low
Inadequate water flow

Type of filtration
Age of tank
RODI water or tap from faucet?
Type of test kits?
Pics of tank ?

 

[Goaway]

Can I ask why you shut the skimmer off at night? Turning the skimmer off at night as well, has been known to drop the ph, significantly. . Not that would kill the fish, but can sometimes kill corals. In order for water to become oxygenated, it must be agitated. Do you have any fish left alive?

 

[davy31]

Some possibilities:
Stray voltage
Tank too new and ammonia spikes --- Ammonia tested to 0 yesterday night and today morning
False test readings
Ph a little low ----> 7.8 based on the test
Inadequate water flow - I have a tunze turbelle 6020 (2500 l/h) and tunze 6015 (1800 l/h) giving out a total flow of 4300 l/h (1135 gal/h)

Type of filtration - Fluval 207 external with bio and mech
Age of tank - 8 months
RODI water or tap from faucet? - RODI
Type of test kits? - Red Sea and Colombo
Pics of tank ?- The second one is older hence you see the fish

 

[thomascameron81]

Definitely would go with low 02 you would be surprised how fast it can deplete

I got real lucky I turned off all my pumps to take some pictures one night and forgot to turn them back on luckily I woke up early that morning And all my fish where still breathing but white and on there sides everything survived but definitely almost lost all my fish due to low 02

 

[davy31]

Can I ask why you shut the skimmer off at night? Turning the skimmer off at night as well, has been known to drop the ph, significantly. . Not that would kill the fish, but can sometimes kill corals. In order for water to become oxygenated, it must be agitated. Do you have any fish left alive?

I turn the skimmer to help with increasing the nitrates in the water, as I increase the feeding I would not want the left overs to be skimmed out. My tank which has only softies and had 5 fish has been running with 0 nitrates and phos over the last month and a half or 2.

I saw the soft corals shrivelling up and not opening, after a brief bacterial bloom a week ago which I think is was Alcaligenes faecalis, my nitrates as of right now is at 0.

 

[chipchipbro]

+1 on the low O2
Und sorry zu hören, dass alle gestorben sind.

 

[Jay Hemdal]

Sorry to hear of your loss.
If the fish ate well the day before, you can rule out fish diseases like velvet.
Low dissolved oxygen is of course the next possibility, but that can often go hand n hand with high carbon dioxide. All tanks benefit from strong aeration (not just circulation) to promote proper gas exchange. Many tanks accomplish that with a protein skimmer. These need to run 24/7. If need be, just stop collecting skimmate as opposed to turning the unit off.
Jay

 

[davy31]

+1 on the low O2
Und sorry zu hören, dass alle gestorben sind.

Danke, ja vielleicht. Also jetzt hab die Strömungspumpen bisschen weiter oben gestellt.

 

[davy31]

Sorry to hear of your loss.
If the fish ate well the day before, you can rule out fish diseases like velvet.
Low dissolved oxygen is of course the next possibility, but that can often go hand n hand with high carbon dioxide. All tanks benefit from strong aeration (not just circulation) to promote proper gas exchange. Many tanks accomplish that with a protein skimmer. These need to run 24/7. If need be, just stop collecting skimmate as opposed to turning the unit off.
Jay

Thanks Jay, yeah I will rectify this today. It is an intank skimmer the aqua medic midi flotor. I am not sure how much control I would have with it. I am also thinking if over feeding could have caused all of them to die. I did feed them 3 times yesterday and I increased the feeding to increase nitrates. But visibly the fish seemed perfectly fine and did not exhibit signs of stress or gasping.

 

[Gtinnel]

I just wanted to say sorry for the loss. I had the same thing happen in my 125g tank a little over a year ago, so I understand how it feels. When I asked on this forum what could've happen the only logical answer that I got was either some sort of contaminant entered the tank or low oxygen. As already mentioned my guess would be low oxygen in your tank.

 

[Lasse]

Low O2 and/or forming of Hydrogen sulphide most likely IMO. Former bacteria blom indicate high DOC concentrations. Did the water smell rotten eggs+ - was the skimmer operating when you saw the dead fish?

Sincerely Lasse