Need help keeping new fish alive.

[GreenSpottedPuffer]

Originally Posted by digital-audiophile

I don't test O2 at home but every once in a while I'll bring a sample into one of the LFS and have them test for me. Unless you water is really stagnant it should not be something you need to worry about testing to often.

To add to this, unless all your fish are dying, I wouldn't worry too much about O2. Its not something that would only effect the new guys.

As digital-audiophile said, as long as you have good surface agitation with the powerheads and your skimmer going, it should be just fine.

Plus you would have noticed your fish breathing very hard and getting quite lethargic.