1 Inch per Gallon Stocking

I've been pondering this for some time already...the 1 inch per gallon stocking rule (or basic guideline). I find it interesting that only length of a fish is implied:

Is a 10 inch oscar in a 10 gallon tank really the same as ten 1 inch neons?

Is 4 inches of long, slender kuhlI loach the same as 4 inches of fancy goldfish?

How about a 3 inch glass catfish, thin as a piece of paper, compared to a 3 inch kribensis?

Or maybe a 4 inch angelfish and a 4 inch hillstream loach?

Do we have to upgrade to area, then volume of a fish?

Any ideas, anyone? (Lets not even go into the discus and freshwwater stingrays)

Oh, and could someone tell me if I'm starting too many threads? I feel kind of bad now.

 

You're not starting too many threads

The examples you brought up are prime examples of why the 1" guideline is just a guideline for smaller fish.
It doesn't take into consideration swim space, waste production, schooling needs or bulk of the fish.

 

I have no idea what the answers to your questions are, but are questions that I have pondered myself. I know it's only a rough rule anyway, and each fish must be considered for it's individual qualities and needs, waste production and so on. I will be watching this thread closely to see what other members who know a whole lot more than me have to say. As for you starting too many threads...are you? Maybe one of the mods can answer that one

edit: Lucy, you beat me - we must have been typing at the same time.

 

edit: Lucy, you beat me - we must have been typing at the same time.

One minute apart. lol

 

Its a horrible rule and should not be used.


Brian

 

I just noticed a link on the words "inch per gallon", and after clicking it, now know why this rule is classified as "rather silly".

 

1 inch per gal.lol ..a Silver Arowana can get 40 inchs long..I don't think it would fit in a 40 gal tank...but I'm sure some one has tried

 

One minute apart. lol

I think Lucy is spying on us somehow.....

 

Its a horrible rule and should not be used.


Brian

I agree 110%. I much prefer to use a surface area rule to allow for the oxygen requirements of the fish. I combine that with research on each fish variety I want to keep. The fishes diet, swimming habits & full grown size will help tell me a lot about how much waste is likely to be produced. Common sense is used combined with all that information to work out what size tank the fish will need & what sort of filtration requirements will be needed.

 

I think the rule is GREAT for beginning fish keepers with small tanks...as well as its advised to help them with the 10 inch oscar in a 10 gallon tank..because god knows the LFS dont!!its a basic starting point to help keep the tanks running smoothly and although more experienced keepers think its horrible or rubbish, remember the beginners who really need to look at it and follow it for sometime ...just my opinion

 

I've always understood the inch per gallong "rule" to loosely apply to fish 2 inches and under. I don't follow it... I have 24 fish in my 30 gallon.

 

I consider the whole thing like pirate "laws..." more like guidelines.

 

Common sense does need to rear it's ugly head from time to time doesn't it? LOL

The inch per gallon rule works best for fish that are not going to get larger that about 3 to 4 inches in their adult form. Most fish that get larger than that also get wider and their space requirements obviously go up as a result.

Lets take an Oscar that has an adult size of 12 inches (this is an example don't side track the thread telling me they get bigger.. LOL). So a 12 inch Oscar has quite a bit of bulk to it. Now common sense tells you a 12 inch Oscar at about 1 to 2 inches wide and 6 to 8 inches high will not comfortably fit in a 12 gallon tank. (Cleanliness aside).

BUT a 12 inch Oscar could fit in a properly shaped 40 gallon tank just fine. Of course his swim space would be limited but you get the idea. Now most people that have kept Oscars know that 40 gallons is not enough due to waste. But the living space would be adequate given good water quality.

Now here comes common sense again... Once you SEE a 12 inch Oscar in a 40 gallon tank you can plainly see it needs more space. Take the same 12 inch Oscar and drop it into a 120 gallon tank and now you can SEE what common sense was telling you all along.

I guess my point is guidelines are there to help the masses get started. They are not "Rules" or written in stone. Research of the particular fish you are going to keep will always be your best bet as well as educating yourself about each new species of fish you decided you would like to parent.

 

I think the rule is GREAT for beginning fish keepers with small tanks...as well as its advised to help them with the 10 inch oscar in a 10 gallon tank..because god knows the LFS dont!!its a basic starting point to help keep the tanks running smoothly and although more experienced keepers think its horrible or rubbish, remember the beginners who really need to look at it and follow it for sometime ...just my opinion

I agree. While I don't personally follow it, I used to when I first started out. It a great rule for newbies to follow, as it gets them THINKING about the adult size of the fish and the limitations of the tank. Once said newbies realize the rule is no good, I think it's safe to say they are no longer newbies. Being able to explain the pitfalls of the rule is indicative of a good general understanding of fish tank mechanics. IMO it's a rite of passage for fishkeeping.

 

Then is there really a guideline for stocking an aquarium (how about 1 cubic inch of fish per gallon)?

 

Then is there really a guideline for stocking an aquarium (how about 1 cubic inch of fish per gallon)?

Experience.

 

Then is there really a guideline for stocking an aquarium (how about 1 cubic inch of fish per gallon)?

None that are really worth repeating, in my opinion.

The fish in our hobby are too diverse in their needs and waste production to boil everything down to an equation that just requires you to plug in a variable or two and get an answer. To paraphrase the points made by a couple of posters earlier in the thread, common sense and research are the best tools to help one understand what their fish need in terms of tank size, not magic formulas.

 

None that are really worth repeating, in my opinion.

The fish in our hobby are too diverse in their needs and waste production to boil everything down to an equation that just requires you to plug in a variable or two and get an answer. To paraphrase the points made by a couple of posters earlier in the thread, common sense and research are the best tools to help one understand what their fish need in terms of tank size, not magic formulas.

Indeed, I couldn't say this any better.

While waste output is the first thing that comes to my mind (some fishies just poop a lot more); there is also the habits of the particular species to consider. Some need to be in schools, and might need more horizontal swimming space, for example, even though their bioload might be relatively low.

 

Don't forget environmental specifics:

Strong current (hillstream loaches)

Planted tank (otocinclus)

Caves (kribensis)

Burrowing substrate (spiny eels)

Tall tank (discus)

Driftwood (clown pleco)

Surface plants (hatchetfish)

Subdued lighting (black ghost knife)

Etc, etc, etc, ...

 

Yep, there is no simple guideline that functions. Look at it more as a complex mathematical equation with a few dozen variables. ;D

I fully agree with Shawnie; for beginners, this guideline, with the quick explanation that it only works with the common small aquarium fish, is invaluable. If followed, it all but guarantees that a decent community tank filled with small community fish isn't overstocked.

 

Let x = fish's length (inches)

Let y = fish's width (inches)

Let z = fish's depth (inches)

Let a = length of tank (inches)

Let b = width of tank (inches)

Let c = depth of tank (inches)

Let n = cubic inches of substrate

Let s = number of fish you could add

Let t = amount of air (empty space) between the surface of water and brI'm of tank (cubic inches)

For example: calculating stocking neons in a standard 10 gallon tank

EQUATION 1: WATER IN TANK

abc - n - t = total volume

Substitue in tank dimensions

(20)(10)(12) - n - t = total volume

2400 - n - t = total volume

Substitute in gravel and empty space

2400 - 400 - 200 = total volume

1800 = total volume

EQUATION 2: GALLONS IN TANK

0.0043 (1800) = gallons

7.74 = gallons [shocking, huh?]

EQUATION 3: CALCULATING FISH

s = 7.74 / xyz / 10

Substitute in dimensions of neons [lets pretend they stay small, just for simplicity]

s = 7.74 / (1)(0.3)(0.5) / 10

s = 7.74 / 0.15 / 10

s = 5.16

s = 5

So in a 10 gallon tank, you could stock roughly 5 neons.

Wait, that makes MY tank horrifically overstocked...

Oh, forget this equation! It's inaccurate.

 

/1

 

Despite its inaccuracy, my wife was impressed by the equation.

 

Well the first two parts in calculating tank volume are accurate...kinda ;D

 

Let x = fish's length (inches)

Let y = fish's width (inches)

Let z = fish's depth (inches)

Let a = length of tank (inches)

Let b = width of tank (inches)

Let c = depth of tank (inches)

Let n = cubic inches of substrate

Let s = number of fish you could add

Let t = amount of air (empty space) between the surface of water and brI'm of tank (cubic inches)

For example: calculating stocking neons in a standard 10 gallon tank

EQUATION 1: WATER IN TANK

abc - n - t = total volume

Substitue in tank dimensions

(20)(10)(12) - n - t = total volume

2400 - n - t = total volume

Substitute in gravel and empty space

2400 - 400 - 200 = total volume

1800 = total volume

EQUATION 2: GALLONS IN TANK

0.0043 (1800) = gallons

7.74 = gallons [shocking, huh?]

EQUATION 3: CALCULATING FISH

s = 7.74 / xyz / 10

Substitute in dimensions of neons [lets pretend they stay small, just for simplicity]

s = 7.74 / (1)(0.3)(0.5) / 10

s = 7.74 / 0.15 / 10

s = 5.16

s = 5

So in a 10 gallon tank, you could stock roughly 5 neons.

Wait, that makes MY tank horrifically overstocked...

Oh, forget this equation! It's inaccurate.

This is 1 part hilarious and 2 parts awesome.

 

Mercy goodness-that formula is a great punishment the next time my daughter gets a failing grade in Math

It's pretty impressive, but following it gave me a headache

 

Oy vey! What a formula!!

 

I think this rule is something you can and should take into consideration when beginning..its a point of beginning for most new keepers....and yes 4-5 inch fish or smaller, is a great comparison...as adults not as juvies....to say this rule is bogus or bull, isn't right as we suggest it daily here with new fish keepers and small tanks...its where ALLOT of us should have started our fish keeping skills(or recommended to start that is)..whether you follow it or not, is your own choice and depending on the level of experience you have, depends on how much you would follow it..

None that are really worth repeating, in my opinion.

The fish in our hobby are too diverse in their needs and waste production to boil everything down to an equation that just requires you to plug in a variable or two and get an answer. To paraphrase the points made by a couple of posters earlier in the thread, common sense and research are the best tools to help one understand what their fish need in terms of tank size, not magic formulas.

BUT...... MOST new fish keepers (I got a tank for christmas,birthday, goldfish at weddings, bettas at birthday parties etc) DO NOT have some of the common sense needed to know where to go and don't know to begin research until something goes wrong...nor will the "1 inch per gallon" rule work when they are members like this.....I know if I speak for myslef, if I had "common sense and research" under my belt, id have never joined fishlore and ive been keeping fish for 15 years....was I doing it properly? nope...do I learn more every day? yep...but if id started out at the 1in per gal rule (as adults) as a beginner, I bet it would have helped me in so many losses over the years......and IMO , its ALWAYS worth repeating if it saves some fish lives and fishkeepers frustrations

 

Hope this post isn't to old I think the surface area rule and the 1 inch a gallon are good used together. Then you compare them.

 

When I started (only a little while ago) I really needed some sort of rule to stop me going out and getting all the wonderful fish that were on offer at my LFS. If there hadn't been some guidance point I would have just carried on overstocking, so I think you're all right to say that the rule is good for newbies. What I can't understand though is why don't you count the fish's tail in the measurement? According to my LFS the guide is one inch of fish body to one gallon of water. So don't the fancy extravagant betta tails take up any room?

 

I think the surface area and number of gallons both should be considered. But there should be a rule possible to compare fish based on mass, would be much more accurate than length. And not really that hard to weigh a fish, you just get a container and tare it to zero and add the fish. Too bad they they don't publish the weight of different fish like land animals.

 

I think the surface area and number of gallons both should be considered. But there should be a rule possible to compare fish based on mass, would be much more accurate than length. And not really that hard to weigh a fish, you just get a container and tare it to zero and add the fish. Too bad they they don't publish the weight of different fish like land animals.

It would be more accurate, but it still wouldn't be accurate.

The reason we focus on the inch per gallon guideline is simplicity. When someone needs a guideline like that, we want it to be simple as possible, because if you try to explain to someone new to a hobby that there are all sorts of variables without giving a relatively easy answer, they get discouraged.

Therefore, we start with "one inch per gallon, and only get fish that stay small... say, three inches or less."

 

I agree that the inch per gallon stocking rule is probably the best for small aquarium with small fish.

With large aquariums, you definitely need another way.

 

I think the best way to check if you are overstocked is dream up a combo, post it on fishlore, and let the experts chew at it until it is perfect!!! Lol!

 

I think the best way to check if you are overstocked is dream up a combo, post it on fishlore, and let the experts chew at it until it is perfect!!! Lol!

+1-that's how I do it any time I'm remotely unsure if a stocking is compatible or if I need ideas on species;D

 

Therefore, we start with "one inch per gallon, and only get fish that stay small... say, three inches or less."

Not to pick on him at all, but this is why I hate this rule. I get the whole its a good starting point, but here is the problem.

fish that are 3" or less should work.
Take a fish everyone is comfortable with, or at least has heard of, a convict.
You tell someone this "rule" even possibly say there is more to it. But they run to the pet shop and get three 2.5" convicts (because every shop in the world seems to have a big supply of them). 2males 1 female or 2 females 1 male doesn't really matter. That's only 7.5" of fish and after all they are three inches or less. They take these fish home and throw them in their new 10gal tank and really in their heart believe they have 2.5" still to go. Might as well grab a Danio or two while they are there.

This is why I hate it. sirdarksol gives good advise and probably get more technical than most on many subjects but here would his advise work with the inch deal. Again not picking on him, which I am sure he knows, just another example of why it would move the hobby in the right direction to get away from it.

We all say but it is a starting point. I do agree to a point with say tropicals I suppose. But if they are here, on this site or any other, why not try to steer them to research what they are getting rather than some wide varying formula? Just a thought.
And I know many will say well we need to make it very easy on new people, but if they are here posting then they know how to use a computer. Google is not hard. Or us helping is not hard. Rather than saying one inch/gallon for small fish for your new 10 gallon tank, suggest an actual species and let them see what they think of it by looking it up. Or make it easy and tell them the information they are looking for about a species, that works also. Either way they get the info about a potential species rather than just I can have 8 of these in a 10 gallon because they fit within the rule.

Just my opinion, this is not an easy hobby, sure we try and make it easier, but the info from members here and the info they could find online would be far better for someone new than just 8 of these like I said before. Part of the problem with the hobby, among many, these days is forums. People come to a forum ask a question then take it as right the second one person responds. Doesn't matter if the answer is right or wrong, someone responded so it must be true. Again my opinion, but if you are not willing to research whatever fish you are getting (saltwater, cichlids, tropicals, bettas, etc.) then you are part of the problem in the hobby today.

This post was not aimed at anyone or any response in this thread. I used sirdarksol response as a starting point but it wasn't aimed at him either. We have had a few threads where we did not agree, one of the good things about the internet and forums are the many opinions.


Brian

 

Gonna have to disagree with you on two points here.
First of all, convicts aren't all that popular for newbies. Barbs, tetras, livebearers, and (sadly) goldfish are much more common for newbies. Much of this is because of the "aggressive" label that convicts have at Petsmart. Sure, there is periodically someone who starts off with these, but there's always going to be people who misinterpret the guidelines (if I ever refer to this as a "rule," it was done in error... I try to always refer to it as a "guideline" and to point out the difference between a rule and a guideline), which is one reason to keep things simple for the new people. If a simple guideline can be misinterpreted, then a complex guideline is much more likely to be misinterpreted.

Second, the convict cichlid is one of the few small, relatively commonly available aquarium fish that doesn't work halfway well with the guideline. Yes, there are going to be exceptions to every guideline, which is why we also say "no matter what, research your fish choices before buying." The guideline refers primarily to matters of bioload (and to some extent, matters of space). It does not account for particularly aggressive or territorial fish.
On top of that, you applied it to a tank that most of us would never suggest for a community tank, anyway. If you look at the "what to put in a 10 gallon tank" posts, you'll see a lot of suggestions for single fish, rather than communities. Those "community" suggestions are usually a few guppies, or maybe a school of neons. It's not until you get to a 20 gallon tank that you can really put a community together.

 

Just wanted to point out that the surface area rule wouldn't take into account the powerheads, and other things adding oxygen.

 

Gonna have to disagree with you on two points here.
First of all, convicts aren't all that popular for newbies. Barbs, tetras, livebearers, and (sadly) goldfish are much more common for newbies. Much of this is because of the "aggressive" label that convicts have at Petsmart. Sure, there is periodically someone who starts off with these, but there's always going to be people who misinterpret the guidelines (if I ever refer to this as a "rule," it was done in error... I try to always refer to it as a "guideline" and to point out the difference between a rule and a guideline), which is one reason to keep things simple for the new people. If a simple guideline can be misinterpreted, then a complex guideline is much more likely to be misinterpreted.

Second, the convict cichlid is one of the few small, relatively commonly available aquarium fish that doesn't work halfway well with the guideline. Yes, there are going to be exceptions to every guideline, which is why we also say "no matter what, research your fish choices before buying." The guideline refers primarily to matters of bioload (and to some extent, matters of space). It does not account for particularly aggressive or territorial fish.
On top of that, you applied it to a tank that most of us would never suggest for a community tank, anyway. If you look at the "what to put in a 10 gallon tank" posts, you'll see a lot of suggestions for single fish, rather than communities. Those "community" suggestions are usually a few guppies, or maybe a school of neons. It's not until you get to a 20 gallon tank that you can really put a community together.

Again like I said I didn't direct it at you I just used what you said, ok maybe it was directed at you, but only because you said it lol.

I didnt say convicts were common for new people in the hbby, I said they were a commonly avaliable fish at many fish shops. And I didnt throw the whole thing in a 10gal. I was saying if someone only took away what you said, the under 3" part, and applied it to a 10 gal they could in fact throw cons in it. Lets face it lots, not all, of people ask a question and get a long response. They remember some of it and apply that as something they learned. Not keeping the whole thing in mind.

My point is, as you agree to, this is a guideline. If people are already here why not give them an actual answer on fish species that will work rather than a guideline? Help them go to the store with diet and water conditions and other factors in their heads instead of just these are small tropicals so I can have X# of them in whatever size tank.
The hard part is done, they are here asking for help, like you said we also always say do you research also. Why not start there?

My main point of the whole post was how the "guideline" could also be confusing. Coming from you, who I also said gives more indepth info on many of your posts than most poeple do, but if I read your post and only retained the one inch/gallon on fish 3" and smaller... it is easy to screw that up if I were new. the convict was just an example, there are easily 50 commonly avaliable cichlids that are small and cute when you see them in your LFS. And we also know these people who work there, 90% of the time, are more into the sale than if the person can house the fish and such.

If we give them a rule/guideline and also say but make sure you research your fish first, all I am saying is could better info not be found/maintained if we cut out this middle man?


Brian

 

My point is, as you agree to, this is a guideline. If people are already here why not give them an actual answer on fish species that will work rather than a guideline? Help them go to the store with diet and water conditions and other factors in their heads instead of just these are small tropicals so I can have X# of them in whatever size tank.

To answer this question:
As my previous posts have said, this is extremely complex. Believe me, it has been tried with many, many members. There are some people, however, who will shut down if they hear this kind of info after they buy a 20 gallon tank. The advice becomes too much to be processed at once, and many of them go out and buy a whole bunch of fish or the wrong species of fish because they misinterpret the complex guidelines we're giving them or simply because they no longer care (it amounts to thinking "I know that keeping fish can't be this complex... the folks at Petsmart said so, so I'll just go ahead and do what they suggest.") This leaves forum members with two options: Type our hands off and then watch as the member loses two or three tankfuls of fish. Or, we can offer a simple guideline that will get the member through the first few months so that they can learn the basics of keeping fish, and then they can move on to learning more complex things.

Take a look at math. Most people can't just jump into algebra, geometry, and calculus. You start with the basics of addition and subtraction. You see that there is a point to them. You move on to multiplication and division, and so on.
Same with fishkeeping. You start out with the simple concepts of maintaining aquaria. There are only so many new tasks a person can learn, and water changes and testing are pretty much absolutely necessary, so making stocking as simple as possible is good. To this end, many people suggest starting with a medium-sized tank (not too hard to maintain water quality, and water-changes aren't too difficult), small fish (they're just easier to work with until you know more about bio-load, etc...), and not too many (this one is important and difficult, because Petsmart is telling people they can have dozens of fish in a 20 gallon tank. The best way to overcome this is with a simple guideline that has a logical explanation behind it).
Once you've got the testing, and you've got the water changes, and you understand that things like hardness and pH aren't all that important, and you know how to cycle new aquaria, then you can start focusing on different things, like more specifics of stocking and how it's more of an art than a science.

To be sure, there are some new fishkeepers who grasp everything right away. The information is here for them, and people are always willing to answer questions that lead to more and more complex info. Such people will figure out very quickly that they are being given simplistic advice and will actively seek out the more complex answers.

Edit: Incidentally, to newer fishkeepers out there; this is not to say that I think any of you are stupid. I was there at one point. Nearly all of us were. It takes a savant to pick up a new set of skills instantly, and most of us are not savants in any area, let alone in fishkeeping.