You might have come across the phrase water column in online discussions.
That’s exactly how I stumbled across the phrase years ago, when I first entered the hobby.
And, when I googled:
What is a water column in aquariums?
It only brought up the water column in relation to oceans… Nothing related to aquariums.
And, nothing there answered my question.
Years later, I see that this question still doesn’t have an online article dedicated to it – so I decided to write one myself!
What is the aquarium water column?
The phrase water column refers to all the water in your aquarium, from the top of your substrate, to the surface water – every last drop.
If your tank has no substrate, then the water column is from the bottom of the tank to the water surface.
To put it simply, the water column just refers to the water that sits inside your tank.
No pebbles, no plants, no fish, no aquarium equipment – just water.
It is important to note that when discussing the water column, it typically does not refer to water that sits in the pipes and filters.
Not too difficult to understand, right?
I can understand where the confusion comes from… Below are two questions I came across in online forums:
1. How do I get rid of algae in my water column?
2. The water in my tank has algae, how do I get rid of it?
Well, it turns out that both of these people asked the same question.
My personal observation is that the term water column is more widely used by experienced hobbyists.
But the phrase ‘water column’ isn’t just used to identify the beginners from those who are more experienced…
It is also used when discussing exactly where a fish prefers to swim in your aquarium.
As you might have noticed with your own fish, different species prefer to swim at certain spots in your aquarium.
If you were to draw imaginary lines in your tank, separating it into thirds, you would notice that fish tend to only occupy one or two areas of your tank.
This is how the water column is most commonly used in discussion – in relation to where a fish spends most of its time.
Danios, Raspora and many Tetra, for instance, prefer the top level of the water column.
Angelfish, Platy and goldfish prefer the middle level of the water column.
And Pleco, Cory and Kuhli loach prefer the bottom level.
By paying attention to what fish swims in which section of the water column, you can build up an exciting community tank with fish inhabiting all areas of your aquarium – not just a single level. How cool is that?
Community tanks that take the water column into account are often much more exciting and pleasing to look at than those that don’t.
If you made it this far, you should now have a complete understanding of the water column. Now, use it in a conversation today!