Oxygen help???

[MANDAMARIE]

Do you have a skimmer in the back? If there is a skimmer then the O2 cannot and will not be low at night. If there is no skimmer, and the water in the back chamber is too high, there will not be enough aeration since there will not be any "waterfall" effect as water flow from the main chamber to the filter chamber. At nigh when the light is out, the O2 level may drop and cause hypoxemia and kill fish, some or all of them. Invert tolerate these episode with no significant problem.
Problem like this can be seen in tank that does not have a sump and does not have a skimmer. I think the LFS may be right in diagnose your problem. If this is the case , fish will died overnight with no visible problem during the day. Can solve this by lower the water in the filter chamber, or put an air stone somewhere in the tank.

Awesome thank you! Still learning so didnt know any of this.

 

[MANDAMARIE]

Chris,
I have a 30 gal cube tank that I used for QT. have 2 MP10 in it for circulation, open top, not glass cover. I have healthy fish died overnight in it due to hypoxemia. I solved that problem by put an air stone in the tank.
It does happen. There are a lot of other factors that compound or mitigated hypoxemia. Health of the fish, number of fish, how active fish are, is there anything else in the tank that consume O2. How much photosynthesis activity going on prior to the light goes out, thus how high the O2 is in the tank before the light goes out and a bunch of other factors.
It is not far fetch, IMO even likely, that MandaMarie's fish is killed with low O2 at night. It happened to me. The inverts and algae are totally unaffected. I use this tank to QT corals, clams and anemones. I don't QT fish. The pair of clown fish that died were a healthy pair of breeding clownfish that I have for long time. I keep them in there when I am trying to shuffle my pairs around. They were fat, healthy and were breeding. They did not died from disease. Here healthy eating up a storm the night before and dead without wound in the AM.

You are saying air stone what exactly is that?

 

[Grape_City_Reefer]

You are saying air stone what exactly is that?

You hook this up to an external air pump and use air hose to push air through the porous body of the "stone"

 

[artieg1]

I imagine everyone reading this remembers being in your shoes. I would recommend not getting more fish (and definitely not coral) until you have had a chance to read up and let your knowledge catch up with your wonderful enthusiasm. I say this because nothing will kill enthusiasm like successive fish deaths. And successive deaths are almost certain as you start out in this hobby unless you go painstakingly slow. I say this as someone who ended up killing a lot of fish at first because I was rushing things. I suspect many of us on this forum started off similarly. I would observe and read and observe and read.

 

[MANDAMARIE]

I imagine everyone reading this remembers being in your shoes. I would recommend not getting more fish (and definitely not coral) until you have had a chance to read up and let your knowledge catch up with your wonderful enthusiasm. I say this because nothing will kill enthusiasm like successive fish deaths. And successive deaths are almost certain as you start out in this hobby unless you go painstakingly slow. I say this as someone who ended up killing a lot of fish at first because I was rushing things. I suspect many of us on this forum started off similarly. I would observe and read and observe and read.

Soooooooo looks like my yellow clown goby is fixen to die he has red spots on him just went to the corner and not moving anymore

 

[Dr. Dendrostein]

Soooo I am new to the hobby and learning everyday! Our tank is 6 weeks and everything has been doing great. Water has been great and stable. We added orange clown and black clown early on and have a yellow clown goby and a blood shrimp. The black clown was the smallest. All fish were doing great and we woke up to our little black one dead. All water levels were good after talking with the LFS they are thinking the levels of the back of our tank were too high and they weren't getting enough oxygen which the night before we found him all fish were acting normal swimming normal and noticed nothing different! How do I know how much water should be in the back and if my fish are getting enough oxygen? I feel terrible bc we are doing everything we are told. Please help!

If home newer, or Furnace old, Furnace can be spewing carbon monoxide, undetectable to humans, possibilities. .......