Fish's favorite...

[Magnum Man]

so, as far as function, most of my tanks are symmetrical ( a filter on each end ), a light that goes all the way across the tank, pretty similar hard scape... I have some that are river like, and have a definite directional flow... but the tank I'm talking about today is nearly identical side to side, ( it's my South American Tetra tank ), and while the fish do swim through out the tank, almost all of the Tetras spend all of there time in about 1/4 of the tank... I can't really find a reason, same flow, same light, same scape, but nearly all day, every day, 80% of the fish, spend their time in a 10 gallon space of a 55 gallon tank, just to the right of the center piece of driftwood... thoughts???

 

[GaryE]

I have something similar in my 120. There are about two feet of it that are really popular. But that section has driftwood and a lot of plants, and I think the tetras like to be in the open current but to be able to scoot into hiding places if I lose my marbles and buy a foot long Crenicichla. They don't trust me.
I also notice an interest in an eddy - a zone where the flow from the Aquaclear 110 meets the flow from the big canister. I assume food is carried there.
This would disappoint the "get rid of your filter and follow me' youtubers, but they seem to like the areas where I suspect the oxygen saturation is higher. Flow and currents we can't necessarily see or predict when we set up create good zones for them.
You can run a lightly stocked tank with no filtration, but I would hate to run one with no strong water movement. That's seems a disservice to the fish to me.

In one of my 75s, I have two equal sized filters at the back, and the zone between them is popular. Again, I think the water swirls as it meets, and they like that.

I don't know how they'd be in a tank with only one filter. A 20 gallon isn't big enough to tell you much, and my tanks over 20 all have 2 filters, sometimes 3 or 4.

 

[Magnum Man]

there are 2 power heads, and 2 Tidal 75's symmetrically placed in this tank...would seem over the driftwood???

 

[CassCats]

I wonder how the shape of that driftwood affects the backflow there, it's got a good shape to be pushing water over it nicely, I'd bet Gary is onto something there regarding that being where some of the food would flow and they'd know it.