1 inch per gallon?

Bad Wolf
  • #1
I understand how the 1 inch per gallon works with multiple fish but what about a single specimen?

eg. say if I got a single 12 inch oscar and nothing else, would it only need 12 gallons? that wouldn't be enough would it?

please tell me more on the 1 inch per gallon rule.

I also like using this method. the fish needs at least 4 times his length, width and height.

eg. a 6 inch long, 2 inch wide and 4 inch tall catfish would need a 24 inch long, 8 inch wide and a 16 inch tall tank. does this method work?

  • #2
Check out this thread BadWolf and see if it helps you.

hmmmmm I can see the point of using the 1" per gallon rule to prevent overstocking in smaller tanks. I've also used the 1 fish per 10 gallon rule for larger fish (which is what I've tried to stay close to in my 155g, although I think it actually comes out to 9g per fish at the moment). As large as my fish are (and elderly), I wouldn't feel comfortable using the 1" rule now cause I would feel over stocked even though I actually have 38"s to spare. Too, I take into consideration the life span of all the fish I plan to stock. The fewer introductions into your tank the less likely your fish will contract disease.
  • #3
the 1" per fish rule is VERY VERY limited in it's application. it pretty much only works for when you have a larger tank that you are trying to ESTIMATE the bioload/swimming space for most AVERAGE sized fish. even then there are exceptions, like goldfish.

even for a full grown angel, a 5 gallon tank wouldn't be big enough. so you are right, the 1" per gallon rule isn't really applicable to large fish, or small tanks.

I wish I could find it, but somewhere someone suggested using something like you said and figuring it cubically as opposed to just a length measurement.

again, it's just a loose guideline and if you have a pretty good feel for your aquarium and test enough, you can find your proper stocking level. if your fish are too territorial, you might not have enough space. or if your nitrates are high all the time, you may be overstocked.
  • #4
As Hawk said, the guideline (it's not a rule. Rules are closer to written in stone. This one is written in Silly Putty) only works for the majority of small, common tropical fish in the industry (guppies, mollies, tetras, etc...). Anything with a particularly wide or tall body, or is particularly long, doesn't fit within the guideline at all.

The example that Hawk is referring to is "one cubic inch per gallon." Oddly, this works okay for larger fish, but not for smaller fish (I'm guessing it takes three or four neons to make up a cubic inch, but I wouldn't put thirty tetras in a 10g).

One fish per 10 gallon doesn't really work, either. It's even more general and doesn't account for larger fish (like oscars, pacu, etc...)

Really, I just use the guideline for a general idea with people new to the hobby who are keeping a typical community tank. If they're going with larger fish, or fish with peculiar aquarium needs, then I refer them to the generally accepted guidelines for those particular fish.
  • #5
preicisely SDS. people just need to cruise around and find all the info they can on the breed of fish they want. Find out what they need tank wise AND water conditions as well.
  • #6
Yes. Research is the most important. Sadly, many people still have this idea that pets are "just animals," and worse, that our finned pets are "just fish," and it's not really necessary to look into how to best care for them. You get them an enclosure (a small cage or aquarium for a rodent, fence for a dog, an aquarium for fish, and your neighborhood for a cat), put some food out for them, and they're good to go, right?
I'm guilty of this, too (though I have learned and am trying to make amends by educating others).
Bad Wolf
  • Thread Starter
  • #7

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