hermit crab + oxygen help

[s & j fisher]

This might be a silly question, but I recently got some blue legged hermit crabs, and someone asked me if they needed oxygen - like if they need to get above the water to breathe or are do they breathe underwater like fish?
Also, between our power head and our protien skimmer there are alot of oxygen bubbles in the water and some are collecting on the fish. I think it looks horrible & distracting with all the bubbles - is there anything I can do to reduce the bubbles? We're afraid to turn the power head down too far cause we're not sure how much oxygen needs to be in the water.
Any suggestions?

 

[sfoister]

Your power head should not be generating any bubbles unless it's too close to the surface and creating a cyclone. Watch it and see. Your skimmer is going to produce bubbles until it's broken in. You could invest in a larger sump with a bubble trap.
The crabs breath like fish. Not exactly like them but to answer your question, they don't need to come up for air because they aren't mammals.

 

[s & j fisher]

Ah, thank you! After adjusting a little, it's working & not creating all those tiny little bubbles that were driving me nuts! I was really considering giving up this hobby if I was going to have to constantly look at those bubbles. You say that the skimmer will produce bubbles until it is broken in... how long does that usually take?
Also, any suggestions on tuning the skimmer? Either our tank is VERY clean or it's not working. It collected foam the first night we put it in after cycling the tank (before we started adding fish) but it hasn't collected any since then.

 

[sfoister]

72 hours for breakin, realistically up to a week, and it won't collect much until it's broken in. Keep it adjusted per your manual.
And if you have just started cycling and breaking in your skimmer you should not have fish yet. If your tank is less than a month old and you've already started worrying about your fish, you need to slow down.

 

[s & j fisher]

Our tank is already cycled. We've had it set up w/ water and only live rock for about a month and 2 weeks and we just now put fish in. Our fish seem to be doing fine, but we were a little curious about the crabs - it's something I never thought about until someone asked me about it. I appologize for any confusion . Thank you for your help.

 

[sfoister]

Your skimmer and the flow from your return pump should be enough to supply oxygen to your tank. I don't have any of my powerheads aimed at the surface, I have mine mounted to the side of the tank about halfway down the side and aimed at my rocks. Aiming them at the rocks will create swirls in the water so you get more of an omnidirectional pattern instead of one continuous flow that could cause certain polyps to elongate.
Worry more about dead spots in your tank, oxygen is rarely an issue unless you have no surface movement at all.

 

[miami298]

I've read that when you setup a new tank that you don't need to or shouldn't run a skimmer until the 2 month mark. I'm sure if you ask around you can get a more definitive answer.

 

[ophiura]

The reason that people ask about the hermits is because there are terrestrial hermits, like you can buy at the beach as a "souvenir." Those hermits would die underwater if left there. But marine hermits stay underwater. So it can be confusing.