How do they do this?

http://www.bloggingwv.com/the-worlds-mo ... -fishtank/

technically i think it is possible, practically it would be a real task. if the space above the water was a vacume then the water may not flow out, kinda like putting a straw into the water, capping the top with your finger & pulling it out, the water won't fall out until air gets to the top.

It would be cool if we had a tank like that in nz where we could go feed the fish

How much vacuum could the fish tollerate, I am assuming that if you tried for too much they would expand and pop at the top of the tank, not pretty.

It would only need to be a little. At the water level of the outlets it would be exactly the same as atmospheric pressure. (If it was more the water would gush out, if it was less air would force in)

It'd be nowhere near enough to make them swell up and pop or anything like that.

i wonder how they do work on the tank if it is airtight

Plug the ports or drain the water level to below them.

More pics on the original photographers site: http://www.cosmicbuddha.com/adam/archives/002230.html

:lol: :lol: some reason the first link took me to a tank that has nothing but couple of plants in pots and surface covered in duckweed. man was i confused.

thanks for the second link Ira

The first link took me to a 'fish highway' which is a very cool idea (as long as the perspex highway remains completely airtight. If it doesn't you get a really big mess!)

The second (c/- Ira) took me to something different. That one has feeding ports below the waterline. Although the concept is the same there is a hell of a lot more to lose in the second one!

Someone commented about "having some fun" and putting a straw in through the feeding port, but that wouldn't work would it? Even a siphon tube should get you nowhere.

so it works with the same reason these things work,

simplr really, hehe :roll: