Moorish Idol - Take 2

[Aquattro]

Originally Posted by tytown

I'm going to turn my skimmer off to see how my emperor, golden, and MI fair with lower oxygenation.
I'll keep you guys posted!

Be careful. I lost a gold flake, blue face and MI to this, presumably

[Samw]

Depending on how large the tank is, it could take a few hours. Lights off will increase the o2 consumption by the tank (algae, bacteria, etc).

[TimT]

If the MI isn't eating yet you need to bring out the fish crack... Pacifica Plankton. I kept a MI alive with it for 3.5yrs. Big, fat and healthy.

Speaking of oxygen demand I just got back from Hanauma Bay where I observed lots of MI pairs and Achilles pairs all in 4 to 8 feet of water and not a lot of current. Even got side swiped by about 300+ convict tangs as they raided the reef where an Achilles pair were living. Their territory was only about 4' by 6' and they were about 7" long. Think I need an Achilles in my 4' by 8' coral tanks. :-)

[Aquattro]

Tim, sorry, mine is eating well on a competitor's shrimps I may have some plankton in the freezer though, I'll try that tonight.

[tytown]

An hour in and I see no noticeable change in fish energy.
Threw some nori in for fun and it was the usual frenzy.
Total volume is over 500 gallons so I'll give it another couple hours. My sump turnover is around 8x per hour which could be a significant source of oxygenation but I would assume that with the skimmer off the DO would drop some...

[gobytron]

One of the most frustrating things about this hobby is the number of variables from tank to tank.

I would imagine that your salt would also play a role in your tanks ability to store oxygen as would it's proximity to outside air...

This could be a pretty neat discovery if it turns out to have some merit.

[Samw]

Originally Posted by tytown

An hour in and I see no noticeable change in fish energy.
Threw some nori in for fun and it was the usual frenzy.
Total volume is over 500 gallons so I'll give it another couple hours. My sump turnover is around 8x per hour which could be a significant source of oxygenation but I would assume that with the skimmer off the DO would drop some...

Are lights off? if you have your lights on and have algae, you would be getting O2 from photosynthethis from the algaes in your tank.

[Aquattro]

Originally Posted by Samw

Are lights off? if you have your lights on and have algae, you would be getting pure O2 from photosynthethis from the algaes in your tank.

Alternatively, lots of algae will contribute CO2 at night, which is when I lost my fish.

[Samw]

Originally Posted by Aquattro

Alternatively, lots of algae will contribute CO2 at night, which is when I lost my fish.

Yes, that's why for this test, one could turn off the lights to increase the depletion of O2 in the tank. See Eric's clownfish tank test where his DO dropped to 16% at night. And overflows are like waterfalls I guess so that is probably oxygenating the water. If that water is coming back into the display at large volumes, then the display tank is oxygenated no matter whether lights are on or off.

[gobytron]

Originally Posted by Samw

Are lights off? if you have your lights on and have algae, you would be getting O2 from photosynthethis from the algaes in your tank.

Even so...
it would seem you two are reporting extreme oxygen sensitivity.

Where do you draw the line for the threshold?

Now it sounds like the average set up with some algae, overflows and such would almost certainly be able to maintain appropriate oxygen levels.