Oxygen complications

[Soilwork]

Hi All,

I know this is dependent but how does lack of oxygen present itself in fish? Can this be a chronic decline rather than just acute issue? For example, could fish that aren’t gasping at the surface still be suffering from oxygen related issues?

Lastly, I notice that this forum does its best to promote oxygen in the aquarium and if you google oxygen and UKAPS there are a lot of threads. Perhaps this fundamental parameter deserves a section of its own? Just a suggestion.

Cheers
CJ

 

[_Maq_]

Can this be a chronic decline rather than just acute issue? For example, could fish that aren’t gasping at the surface still be suffering from oxygen related issues?

Definitely so. Most fish reportedly gasp at the surface below 1.5 to 3.0 mg/L. However, norms for commercial fish breeding demand 5 and more mg/L (depending on species) because lower levels result in higher mortality and lower growth.
In ornamental aquarium, chronic lack of oxygen may easily occur when overfeeding or keeping too many fish. All fish food ends as a "food" for microbes and these microbes respire oxygen. Microbes are normally invisible, so inexperienced hobbyist may easily miss any warning signs - plants may drop their lower leaves prematurely, fishes behave less lively, some snails tend to advance toward the surface, and all of this is often accompanied by increased algae growth.