# tank size



## Flear (Oct 5, 2012)

while calculating tank sizes for fish (aside from some specific species), ... i've arbitrarily decided upon 10 gallons per inch, ... a fish with a 6" adult size is generally listed as 55 gallon tank min. (this is my thinking)

great gallons per inch, ... but gallons are volume and not size, ... a tank could be short or tall, and this would change the area of the tank base, ... and in turn change how much room the fish has to move around in.

i have heard "so long as the fish can move around comfortably"

now i'm going to ask what appears to be a simple silly question, ... "what does this mean"

-a fish at a 6" length
-is 8" comfortable to move around in, or 10", or 12", or 18" ?
(going by the short side of the tank)

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tank sizes have a general typical shape, ... but ... i get curious about custom tanks, ... would suck to build a tank and think "hey, this fits the numbers, but the fish is not comfortable at all"


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## Austin (Feb 1, 2010)

I think it's practically all guesswork to begin with. It's hard to determine if a fish is comfortable except for obvious signs.


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## jaysee (Dec 9, 2009)

First things first, not all fish have the same spacial needs so there isn't a one size fits all rule. By and large though, schooling fish are all generally the same. 

My own guideline for schooling fish is 1 foot of tank for 1 inch of fish as a minimum. So a school of neons would need a 2 foot log tank since they are 2 inches long. A school of rainbows would need at least a 4 foot long tank because they are 4 inches long. Denison barbs a 6 foot tank because they are 6 inches long.


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## Flear (Oct 5, 2012)

Jaysee, i like that rule-of-thumb


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## jaysee (Dec 9, 2009)

Fish like cichlids and plecos don't need as high of a tank length to body length ratio because of their territorial nature. Cichlid stocking is much trickier as different specimens will claim different size territories. While you can stock cichlids of different sizes together (larger cichlids don't usually consider smaller species a threat), any time you mix New World cichlids it's still largely trial and error. Africans are another matter, on which I defer to my girlfriend.


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