Can you keep fish completely submerged?

The short is, probably not… their entire lives.

Most fish can carry out their entire respiration by way of gills, however, some fish that are adapted to poorly oxygenated waters such as the catfish and labyrinth fishes (e.g. Siamese fighters, gouramis), require access to the water surface to breathe. Otherwise, they will most certainly drown! Yes, fish can drown!

On the other hand, the proper functioning of the swimbladder of physostomes requires gulping air to fill it. And this process is also vital in the fry swim up phase during early development.

But what about adult salmon? Why the reason for such research? Some people view aquaculture pens as visual pollution. Also, some farm sites are too rough for surface farms. And so, underwater net pen designs maybe necessary.

Read more in the abstract of the article below as it relates to salmonids:

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Aquacultural Engineering
Volume 51, Number 11 (November 2012)
	Atlantic salmon (Salmo salarL.) in a submerged sea-cage adapt rapidly to re-fill their swim bladders in an underwater air filled dome
	Authors:	Øyvind J. Korsøen1,2, Jan Erik Fosseidengen 1, Tore S. Kristiansen 1, Frode Oppedal 1, Samantha Bui 3, Tim Dempster 3
	Author Affiliations:	1: Institute of Marine Research, NO-5984 Matredal, Norway 2: Centre for Research-based Innovation in Aquaculture Technology (CREATE), SINTEF Fisheries and Aquaculture, 7465 Trondheim, Norway 3: Sustainable Aquaculture Laboratory – Temperate and Tropical (SALTT), Department of Zoology, University of Melbourne, Victoria 3010, Australia
	Source:	Aquacultural Engineering, Volume 51, Number 11 (November 2012)
	Page Numbers:	1 – 6
	Available Full Text:	Full Text: Subscription Required to view full text Format: PDF Size: Unknown Location: Publisher’s Site Authentication: Publisher’s Site
	Abstract:	? Submergence of salmon is unfeasible as swimbladder gas leakage reduces growth. ? A submerged air filled dome was tested to see if salmon can refill their swimbladder. ? Salmon rapidly and repeatedly swallowed air from the underwater dome. ? The results demonstrate that salmon can adapt to use underwater air domes.
	Citation:	Øyvind J. Korsøen, Jan Erik Fosseidengen, Tore S. Kristiansen, Frode Oppedal, Samantha Bui, Tim Dempster . Atlantic salmon (Salmo salarL.) in a submerged sea-cage adapt rapidly to re-fill their swim bladders in an underwater air filled dome. Aquacultural Engineering, Volume 51, Number 11 (November 2012), pp. 1-6, ;
	URL:	http://ejournals.ebsco.com/direct.asp?ArticleID=452ABCD5BFD3551C8190