The dreaded 1 inch per gallon rule

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Charlie Greiner

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Jul 25, 2007
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Has anyone thought of this creatively? "But honey, I know you care about the fish and can see they are way too crowded for their health. We seriously need that 25,000 gallon tank.Even if it means a new mortgage."
 

Danyal

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May 20, 2007
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I can understand where they are going with it but it is as inaccurate as the 1" per gallon rule as well. It all depends on the fish. The way it should be is 1 gallon per cubic inch of fish. using a 6" Cichlid as an example:
Typically it would be 6" long about 4.0" high and about 1.5" wide.
1G per 1" = a minimum 6 gallon tank (too small)
By table above it needs to be a minimum 216 gallon tank.
1G per cubic inch = a minimum 36G tank
A fully grown Oscar at 12" long 6" high and 3" wide would require a 216 gallon tank where by the chart above you would need a 1,728 gallon tank.
Anyhow, that's just my opinion and that is how I usually set up my tanks for stocking.
As for fish waste, That would deal more with filtration rather than tank size.
you just proved that the cubic inch per gallon, while much better than the inch per gallon, still doesn't work. for a 12" oscar, while it would be great for a 216g tank, the minimum tank size would be a 75g.
 

kjr928

Go fish yourself.
I think someone should come up with a point system for fish based on how they affect bioload.

So maybe neons would be 1 point and dwarf gouramis would be 4 points and rainbow sharks would be 12 points (or whatever). When you add up your fish they need to equal less than your # of gallons.

I think that would work for at least some of the common FW aquarium fish. It would be like Weight Watchers for fish!
 
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cherule

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Jan 6, 2007
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I figured this topic would get a good response! Hehehe! I'll quote more of the article as it helps to clarify their point.

There was a third column in the chart that gives minimum gallons per fish of the various lengths. As some have said, mass does not equal gallons per fish.

They suggest:

1 in === 1 gallon
2 ===== 2
3 ===== 3
4 ===== 5
5 ===== 8
6 ===== 10+
7 ===== 12+
8 ===== 15+
9 ===== 18+
10 ==== 20+
11 ==== 30+
12 ==== 40+
24 ==== 75+

They go on to say: "These figures assume 50% or more weekly partial water changes. Even then, waste may build up too quickly. Use common sense, too. A 20-gallon tank is too small for a 10-inch fish, but it's all right to allot 20 gallons of a 75-gallon tank for it."

"...rules aren't written in stone. A fish may be a hundred times bigger than another fish in mass, but that doesn't mean it eats a hundred times the amount of food. It's the waste build-up that's the danger more than the size of the space."

The author also mentions an experiment he saw "in which trout were raised in tight confinement. The scientists put about a half-dozen fingerlings into a gallon-sized acrylic tube, then plumbed it so that fresh water ran continuously in one end and out the other. The water was not recycled. There was no way for waste to build up. The fish grew until they were packed almost as tightly as sardines. Clearly, the size of the container isn't the issue."

Disregarding the obvious quality of life issues in an "experiment", I think he does prove a point about water quality. There are clearly many opinions around the issue of overstocking, thriving vs surviving...etc.

All info is grist for the mill. Hopefully, this kind of article gets people thinking about how to provide the best home we can for our fishy buddies. Knowledge is power! ;)
 

wolf13

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Mar 13, 2007
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I stumbled on this last year:
http://www.plecofanatics.com/forum/showthread.php?t=16911&highlight=stocking+shane

Post #7 Is shanes stocking guide. Its actually not a bad start, but is a bit conservitive perhaps for some tanks I think since it only takes into account surface area and not depth or overall gallons in any way and only really deals with oxygen exchange capacity in its intial setup.

theres lots of factors like behavior, territoriality, stratification, planted vs non planted, filter efficiancy etc that aren't taken into account that can effect what a tank can actually hold optimumly.
 
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Rbishop

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wolf is correct...there are too many other factors that are really more important in judging the stocking. I see more inappropriately stocked tanks than I do over stocked tank issues.
 

Vienna002

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Sep 29, 2006
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i go along with the common sense theory as well as my opinion that you can have more fish than suggested as long as they are all comfortable and you do more water changes to help with the waste issues
 

jm1212

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Jul 22, 2006
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so then a 24" fish is going to need a 13,800g tank? i'm so freakin tired of these crappy rules.
what they are saying is not that a 24" fish needs a 13K tank, but that it takes 13K one inch fish (i.e neons) to account for the same bioload.
 
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