When swimming, a fish must displace some amount of water from front to behind, since water is incompressible. This movement must (I suppose) create some wave at the surface. The wave will be distributed according to the distance from the fish to the surface, as you said. Anyway, since there are a lot of fish in the sea, there should always be some waves even without any wind.

In your tank, when the fish are swimming, do you observe anything like that or is the surface perfectly calm?

I use an outside filter that pours the water into the tank creating waves for aeration. I have seen fish swimming just under the surface of very still water cause swirls and waves but as they go deeper the effect gets lost.

When swimming, a fish must displace some amount of water from front to behind, since water is incompressible. This movement must (I suppose) create some wave at the surface. The wave will be distributed according to the distance from the fish to the surface, as you said. Anyway, since there are a lot of fish in the sea, there should always be some waves even without any wind.

In your tank, when the fish are swimming, do you observe anything like that or is the surface perfectly calm?

I have given this some thought and I have to ask are you thinking of solitons? The best way to observe them is in a round swimming pool with a pump and cases the water to go around in circles. They form and dissipate on the surface but are too small to see but you can see their shadows on the bottom in full sunlight.

I have given this some thought and I have to ask are you thinking of solitons? The best way to observe them is in a round swimming pool with a pump and cases the water to go around in circles. They form and dissipate on the surface but are too small to see but you can see their shadows on the bottom in full sunlight.

No, i was thinking about the butterfly effect.

In fact I was thinking that the butterfly effect does not appear, IOW you do not observe a large wave coming out from the fact that small fishes are swimming in an aquarium.

No, i was thinking about the butterfly effect.

In fact I was thinking that the butterfly effect does not appear, IOW you do not observe a large wave coming out from the fact that small fishes are swimming in an aquarium.

You are correct you don't see that, waves dissipate instead of building and they have to be at the surface for the waves to be seen. Now I have seen a big fish in the wild disturb the surface from a foot or so under the water but it was a very big fish.

Also I have to admit i have no idea how swims a fish.

Also I have to admit i have no idea how swims a fish.

Some fish are more hydrodynamic than others.

New aquarium set up, all the pieces are there now to arranging them, the black rock to the left is a piece of coal i found on the beach, part of a civil war blockade runner cargo that never made it to port...

 

A video taken this summer at our NC convention of fiery black shiners mating combat! NANFA

 

This is my new 75 gallon set up, old tank new rocks and bogwood. It contains pink lipped shiners, chubs, black banded sunfish and the yellow bullhead is seen exploring his new digs. I caught all the fish my self in my home state of NC.

 

It needs a Christmas tree (worm).

 

http://youtu.be/4kGVfn0czK0?t=1m40s

Edited December 10, 201411 yr by MonDie

 

It needs a Christmas tree (worm).

 

http://youtu.be/4kGVfn0czK0?t=1m40s

 

 

They are pretty but they don't live in freshwater...