I have a 75 gallon tank with a Sunsun / Aquatop canister filter rated at 264 gph coming out of a spray bar on the side of the tank as well as some air bubbles.not bad, just make sure your co2 level is not to high or u'll gas them. do u have plants? if not, no reasons to use co2. but make sure u have lots of flow. these guys love high flow water.
How do I make sure O2 levels are good? Just look to see how many dead fish there are ?CO2 and O2 are not mutually exclusive, you can have both.
First make sure O2 levels are good, then increase CO2 to deal with extra surface agitation.
A well planted tank with good lighting will have higher O2 than not, while getting CO2.
Is injected Co2 only done when plants are dying from lack of Co2?CO2 injection should only be used when there's a large amount of healthy, fast growing plants. If you are concerned about having too much CO2, don't buy the equipment, don't heavily stock your tank with plants. You can do well with less injection using a 1.3 liter, yeast/sugar DIY bottle. Depends on how big the tank is you are growing them in.
What would be more important with Denison Barbs is having adequate water circulation and reduced temperatures, running 70~74 degrees. This will increase the oxygen levels.
I am saying that when I look up plants online, some of them say Co2 medium, Co2 high requirement,etc..It occurs to me that if one is not able to grow plants without CO2 you're probably doing something wrong.
It's not my job to run further down the rabbit hole the OP presented about Mormons and alcohol...
Is that only true to a certain level? At a certain point, if you have too much Co2, then there is no room for oxygen?While CO2 and O2 don't displace each other, and you can have plenty of both dissolved in the water, doesn't mean the livestock is able to get enough O2 in their blood when there is high levels of CO2.