donut tank

snookman · Post by **snookman** » 03 Oct 2004, 22:10

has anyone ever seen or used a round tank shaped like a donut with current so that the fish would swim in a circle against current? Just wondering.

Post by **medaka** » 04 Oct 2004, 00:31

hi snookman
I hope you don't think me picky

but..
if a tank is made circular .and you put say; power heads pointing in the same direction as to create current flow.. how would you make the fish swim against the current,, if they chose to swim in the other direction round the tank

saying that . many years ago there was an advert in tfh
for a company that made acrylics tanks to any size and shape their advert featured a circular tank

snookman · Post by **snookman** » 04 Oct 2004, 00:46

i wasn't implying that the fish HAD to swim against the current...just that most fish face head-on into the current.

MonkeeFish · Post by **MonkeeFish** » 08 Nov 2004, 06:25

peacock bass had a huge circular pond???

racoll · Post by **racoll** » 09 Nov 2004, 09:56

like the sort you get in sea-life centres!

impressive, but the curved acrylic would distort the image of the fish i think. not desirable.

coelacanth · Post by **coelacanth** » 09 Nov 2004, 18:05

snookman wrote:...just that most fish face head-on into the current.

It's called rheotaxis. You can get the same effect in a round tank as long as the inlets are positioned correctly, no need for a 'donut'. It used to be used on a very large scale to try to house sharks that were ram-ventilators.
I've seen it used for shoaling fish like Scombrids and Clupeids, and is quite commonly used in intensive fishfarming.

snookman · Post by **snookman** » 09 Nov 2004, 21:40

since the last post i made on this thread i've actually come up with a diy tank that i'm going to build. haven't priced it yet though. it will be an octagon tank (not hex) measuring approx. 56.5in from panel to opposite panel. this makes each of the 8 panels 24in wide and the tank will be 30 in high. calculated to about 34o gallons or so. i'm gonna use 2 powerheads to make the acclaimed circular current. it will also be an under dock simulation... partially planted...most likely a sand substrate. it's large enough to keep the under dock area to about half of the tank leaving enough room for other rocks and driftwood. i am still trying to decide if 1/2in acrylic will be enough, or if i should go with 3/4in. i'm also building a stand and canopy. the stands will be 60"x60"x30" square...leaving 4 triangular shelves on each corner. the stand will have a support area at the base of the entire tank where the greatest pressure is and i have designed a custom acrylic top for support with access holes cut out with all corners having a 2"radius. needless to say...big project!!! i just hope to be able to start it within the next year as i want to have thoroughly researched every aspect of the design, cost, filtration, placement, etc. anyways...just wanted to share. any suggestions/things to look out for, on any of the above mentioned tank specs or research criteria would be appreciated. thanks.

snookman · Post by **snookman** » 18 Nov 2004, 19:37

any help on thew aforementioned criteria???

aquaholic · Post by **aquaholic** » 19 Nov 2004, 14:20

I've been to a public aquarium near Tokyo which has a donut shaped tank. http://www.tcvb.or.jp/en/infomation/7recom/sem2.html
They have beed keeping massive pelagic tuna successfully (world first) for years. You can sit in comfort in the centre and watch 3-4m fish swim all around and past you or view via underwater cameras from armchair monitors. Impressive seeing huge fish swim head on into you.