The "one inch per gallon" rule

chimbakka

Feeder Fish
Sep 10, 2007
3
0
0
Kitchener, ON
BushFishRox;1104955; said:
12" of water times 12" of fish is 144" or 12ft so I just folded that in half rather then say you need a 12'x1' tank...

or do you really mean 1" of fish per 1"sq of water? since you say a 12" fish would need 1/12 of a 12sq ft tank? because the way you word it means that a 12" fish needs 1sq ft of water...
surface area is in sq inches
so for a 12" fish you would want 144"sq which is only 12"x12" piece of the tank
so if you tank is 36"x12" you would have 432"sq to use
I think this would work well for smaller species, but a 12" fish is gonna need more space than 3' to swim I would think.
for a 3" fish you could have 12 in this size tank... this size would be about 35 gal right? so by the inch/gal you could have 12 fish about. seems good to me.
 

chimbakka

Feeder Fish
Sep 10, 2007
3
0
0
Kitchener, ON
Bderick67;1107597; said:
:screwy:
You really have no idea do you? The formula as you explain it does does not work. A single neon needs more then a 3" x 4" area to swim in. A 6" jack dempsey needs more then a 6" x 12" area to swim and we already know about the oscar. With Bushfish explanation at least fish have room to swim, but way more then needed though, so neither interpitation works. This thread is meant as a guide for beginning fish keepers and to sit and argue this is only going to add to any confusion that the beginner already has.

The modified one inch per gallon rule works. The surface area per fish does not.
i don't think they intend that you buy a 3"x4" tank
just as you wouldn't buy a 3 gal tank for a barb
it's supposed to be used with a WHOLE tank to find how many fish are good for it
 

Bderick67

Bronze Tier VIP
MFK Member
Aug 18, 2006
16,813
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Colorado
shinypenny;1123623; said:
and by the other rule we have 12x10x4x1.5 = 720 square inches

or a surface area of 48"x15"

which gives a standard a 55gallon tank (48x15x18)

So as I was saying the results when using the two methods correctly are aproximatly the same.

Wrong again The rule as stated below does not work, If you keep manipulating the rule you will get it to work though as you have shown.

snakehead121;1098584; said:
cool guppy, I have used a diffrent method befor. First you find the serface area (length by width). Then for your fish for tropical freshwater 12in. per 1in. of fish, for cold freshwater 28in.(I think it may be 20), and for saltwater 48in. And for fish that go to the serface to breath double the in. requierd.
for this rule as it states a 10" jack dempsey would get 120" of swimming space. Now if ya modify the rule and also multiply the fish's width 1.5" and heigth 4" which "shinnypenny" has done you can make it work.

But until modified or clarified by "snakehead121" this rule is incorrect and should not be used. If your are trying to figure stocking levels for your tank, please use the "one inch per gallon rule" as posted by "Guppy"

The confusion stated in the posts below are from a newbie trying to interpet the rule posted by snakehead.


chimbakka;1128626; said:
surface area is in sq inches
so for a 12" fish you would want 144"sq which is only 12"x12" piece of the tank
so if you tank is 36"x12" you would have 432"sq to use
I think this would work well for smaller species, but a 12" fish is gonna need more space than 3' to swim I would think.
for a 3" fish you could have 12 in this size tank... this size would be about 35 gal right? so by the inch/gal you could have 12 fish about. seems good to me.
chimbakka;1128629; said:
i don't think they intend that you buy a 3"x4" tank
just as you wouldn't buy a 3 gal tank for a barb
it's supposed to be used with a WHOLE tank to find how many fish are good for it
 

TheBloodyIrish

Feeder Fish
Mar 3, 2007
1,347
1
0
Grande Prairie, Canada
Instead of gallonage... we should go with footprint like herptile people do.
 

Bderick67

Bronze Tier VIP
MFK Member
Aug 18, 2006
16,813
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857
Colorado
TheBloodyIrish;1129258; said:
Instead of gallonage... we should go with footprint like herptile people do.
With the larger fish kept most people do. This thread is set up for clarification of the "one inch rule" to guide beginning aquarists.
 

thatonegirl

Feeder Fish
MFK Member
Interesting thread. I work in the fish room of a great LPS and I have to explain away myths about stocking rules daily. I always try to break it down this way to people: As fish grow linerally, their mass increases exponentially so the mass of a ten inch oscar is equal to that of about 100 white clouds. The more mass a fish has, the more waste it is going to produce. Allowing that a tank is big enough for a fish to turn around in and have at least 4 times its body length for swimming is one important part of making sure it is comfortable, but how much maintenace you need to do is dependant on how much waste is being produced.

If you choose to overstock a tank, you're going to have a lot more work on your hands when it comes to cleaning up after your charges. My 125 gallon tank is overstocked and I would never recommend to a beginner what I get away with in my own tanks, but I also do a lot of water testing and water changes and use live plants to help maintain nitrate levels.

I don't feel comfortable with any of these rules because the only one I can think of that applies to every sort of situation is that there are going to be exceptions to every rule.
 

dielikemoviestars

Feeder Fish
MFK Member
Sep 20, 2007
15
0
0
California
Interesting look at the "rule." I've also found a "rule" that compares the length to the surface area of the tank, for oxygen levels. Never really followed either of them, but this one seems more reasonable.
 

Saskia

Feeder Fish
Sep 26, 2007
3
0
0
Australia
This may be a pain - but could you convert your statistics into cm and litres? In AUS we don't use gallons/inches and am not sure of the conversion. Thanks - great info
Saskia
 

guppy

Small Squiggly Thing
Apr 15, 2005
11,582
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0
confused, lost, and lonely
Saskia;1160182; said:
This may be a pain - but could you convert your statistics into cm and litres? In AUS we don't use gallons/inches and am not sure of the conversion. Thanks - great info
Saskia

Try 2.5 cubic centimeters of fish for every 4 liters of water. This is a fairly generous ratio.
 
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