The "inch per gallon rule" .... Variations

The "inch per gallon rule" says 1 inch of full grown fish per gallon of water. But as someone pointed out to me a Molly is fatter then a Neon so it is more of a bio-load.
So: per the rule, does a Molly count double or does a Neon count half ?
PS: I think it would be a good idea to have a "Stocking" category on the site.
Drew

 

Drew,

The inch per gallon rule is not really the rule. You wouldnt want a 10" pleco in a 10 gallon tank. You have to use judgment on things like that. I know my Mollies are huge waste producers so they "take up" more space. I would consider them more of a 3-4" fish just because of the waste. A better rule of thumb would be to consider bio-load as opposed to inches, that might help you better.

 

The 1" per gallon is more of a general guideline then a rule. Unfortunately I have not been able to find any documentation that suggests waste output for different fish. As such I could only guess if a neon should be considered an 1” or ½” ect. Which regrettably brings us back to the “guideline”.

I believe your best option for determining your stock for any given aquarium is to slowly add fish until such time the aquarium can not handle the ammonia output in a 12 hour period.

 

There is a stocking category on this site! its under "More Freshwater Aquarium Topics".

 

Another thing to think about is the space the fish uses. How does it swim. Fast, slow. . .Is it a territorial fish? Does it school and stay close with its kind? Is it a bottom dweller, mid-level or top level swimmer. I think you need to pay attention also to where they come from too. Lots of variables to think about which really makes it interesting to do research.

 

I believe your best option for determining your stock for any given aquarium is to slowly add fish until such time the aquarium can not handle the ammonia output in a 12 hour period.

Also, even if your tank can process the ammonia, more ammonia leads to more nitrites, which leads to more nitrates, which leads to more water changes.

So it really is just a matter of observation and judgment.

 

Cool

Drew,

The inch per gallon rule is not really the rule. You wouldnt want a 10" pleco in a 10 gallon tank. You have to use judgment on things like that. I know my Mollies are huge waste producers so they "take up" more space. I would consider them more of a 3-4" fish just because of the waste. A better rule of thumb would be to consider bio-load as opposed to inches, that might help you better.

Cool. What is the Bio-Load rule ?

 

Thank you

There is a stocking category on this site! its under "More Freshwater Aquarium Topics".

Thank you.

 

The first thing I read............

The 1" per gallon is more of a general guideline then a rule. Unfortunately I have not been able to find any documentation that suggests waste output for different fish. As such I could only guess if a neon should be considered an 1” or ½” ect. Which regrettably brings us back to the “guideline”.

When I first came to this site I was directed to read a "Beginners" article. It said:
Overcrowding: It's worth overstating: please start with very few fish. You'll have a much more individual relationship with each of the fish, and it's so much nicer to see happy, comfortable fish, than to wonder what's wrong every 2 minutes because they suffer from the overcrowding. The rule of thumb is: 1 inch of fully grown fish per gallon. This will make maintenance (fish can poop for England) much more manageable. Of course, do read up on your fish' individual requirements in terms of companionship. Some are schooling fish. (Armadillo)

 

That rule is only for fish under 2 or three gallons. For instance, technically plecos get around 20 inches long, but you cannot keep them in a 20 gallon tank, not only because of a lack of space, but because they poop a TON and will pollute the tank. Another example is the dwarf puffer. They're tiny, only about an inch, but need to be in at LEAST 5 gallons tanks, and they are very aggressive, so you couldn't keep them in community, no matter how large the tank was. It depends on the nature, size, and bioload of the fish. So when you want a new addition, ask around here, someone will know if said fish will work in your tank.

 

... It also depends the tank in which the fish is located. It is not the same to overstock 5 inches in a 55 gallon than 5 inches in a 5 gallon