How much surface area is required?

[johndierks]

So I'm new here, I've always liked having fish, but it's never been a huge hobby of mine. I've got a really cool idea for a fish tank, so I've been researching about building tanks, etc.

I've got a general question, not so much about tank construction, but more about fish health. My idea for the tank is such that the tank would not have loads of surface area in proportion to the volume of water. I'm not sure if having a lot of air/water interface is important for fish health, so I was wondering what you guys can say about that. The tank will be about 20 gallons, and I'm currently estimating the surface to be about half a square foot, basically enough room to feed the fish, provide way to perform basic cleaning and maintenance, and allow air to bubble out. Comments?


I'm planning on having a pretty run of the mill, freshwater, pet store fish tank. Nothing too exotic.

 

[daveedka]

As a general rule, larger surface area tanks are easier to deal with.
low surface area is low area for gas exchange, thus less 02 for the fish and a need for more aireation and excellent circulation. it also typically means a tall tank which comes with lighting problems and swimming area problems as well. All of these issues can be dealt with or worked around but they do require extra consideration. Very few people like or reccomend tanks with a low surface area ratio, But that does not make them impossible or improper IMO just more difficult in some ways than a standard tank.
dave

 

[RTR]

One of the biggest issues in low surface area tanks is the upkeep access daveeka mentioned. Another is the worst-case scenario of extended power outages - my stocking is generally low enough that my setups can survive with nearly hundred-years ago conditions lacking current and efficient filtration - meaning the gas exchange with still water is still sufficient to provide for the fish's survival at least. With only half a square foot of surface, I would not count on survival of more than a handfull of the smaller community fish in an extended outage.

 

[chkltcow]

Okay either my math is wrong, or your math is wrong..... or.... you're insane.

My 20g tank is 30x12".... 360 square inches. Correct?
If you do one that is half a square foot, that's 72 square inches.... correct?
sqrt(72)=~8.5

So, if you do a 8.5" cube, or for that matter ANYTHING that figures up to 1/2 sq ft of water surface, it would have to be over 5' tall to get 20 gallons of water in it. There is no way I can see that working, and you would only be able to keep a few fish in it, even as big as it is... and none of the fish over about 3" long or they could barely move.

I'm confused here... give us some real measurements.

 

[johndierks]

Okay either my math is wrong, or your math is wrong..... or.... you're insane.

The answer is D: None of the above.

Basically the initial idea was to build a coffee table fish tank. One of the problems with such a tank is that when looking at the tank from above, you are looking through glass, then through air, and then through the surface of the water, making it hard to see the fish well. So I set about trying to figure out a good way to built a fish tank that when viewed from above, you can see right into the water. The way to do this is to remove the air/water interface. This is what I've come up with.

It's turned into a side table, instead of coffee table, because a) it's most natural to have the tall part against the wall, and b) my apartment building only allows fish tanks up to 30 gallons.

Regarding upkeep, my idea is to have the top piece of glass removable, probably with silicon gasket and some sort of compression fittings, so I can drain the water, so it's below the main inside of the tank, and then remove the top, and viola, the surface area is huge, over 2 square feet. This will make cleaning the tank much easier, and would make a power loss a non issue.