"Inch per gallon rule" think good filtration is key?

[AquaticQueen]

Hello, fellow fish keepers!
I have wanted to post this for a while. I was wondering who uses the "inch per gallon rule" and who doesn't so I decided to put it to a vote.
I guess it isn't really voting but it's the only way for me to find out.
Well, anyway please vote on which ever you use for stocking.

 

[Gone]

You shouldn't have a 10-inch fish in a 10G aquarium.

The inch per gallon rule might work with one-inch fish, but it's more dependent on filtration and water changes.

 

[Wardonianfungus]

I’m in between. I agree with the above, I wouldn’t put an ocsar in a ten gallon but for most species I use a combo of the inch per and common sense. I also keep heavily filtrate tanks though.

 

[bmuckluck]

I agree, I don't think it is clean cut- a five inch goldfish will create much more waste than a 5 inch catfish, from my experience anyways. Depends on the type of fish, where it likes to swim, it's behaviour, whether its tall species (like an angelfish) or a long species which needs more room longitudinal wise, all have different ideal size/shape tanks.

 

[Prest12]

I do not use the inch per gallon rule. Filtration isn't the only problem. You also have to consider swimming space. A common example is a 10 inch oscar in a 10 gallon tank. With the tank being only 20 inches long and 10 inches deep (wide), how is the oscar supposed to get anywhere? While the inch per gallon rule may kind of work for tiny fish, that's about all it's good for.

Edit: Seems I've been beat (no surprise, I take forever to write these things).

 

[tnrsmomma]

Ditto what others already said about size, shape and swimming habits of a fish. 5 or 6 zebra danios would be ok in a 10 gallon per the 1 inch rule but they love to zip around and swim fast. There isn't room for that in a 10g.

In terms of filtration, I think live plants are a huge part of it. Plants are really just another type of/addition to filtration. I would stock my tanks a lot lighter if I didnt have live plants. I have double the recommended filtration on everything too though.

Maintenance and free time are key. My 10 gallon is low stocked for how filtered and planted it is because I don't want to deal with frequent water changes. I do about 30% on that tank every 3 weeks. My other tanks need way more attention for their relatively high stocking to filtration/plants/maturity ratio. I have to do partial WC on the 29 gallon every 5 days. The 20 gallon long is about the same schedule since its brand new and still finding its balance. That's another thing. I'd be much more likely to "overstock" a mature tank than a new one. In the 20long right now all it has is 10 neon tetras and some amano shrimp. I jump started it with a seeded filter, plus drift wood and plants from other tanks, but it still has to adjust a bit to the bioload of the fish and has lots of surfaces that need to grow bacteria and biofilm before I would want to dump in more stock.

 

[bumblinBee]

The inch per gallon rule is a guideline for beginners. Experienced hobbyists can make appropriate judgement calls because they have a more thorough understanding of the nitrogen cycle, as well as different species, and their individual care requirements.

Although the inch per gallon rule is flawed (as others have already pointed out with the 10 inch fish in 10 gallons analogy), I think it can still be used as a useful tool.. When you set up your first aquarium, you have no baseline to refer back to. First timers will overstock. So this simple rule, although fallible, still serves a purpose within the hobby, IMHO. I used the rule when I started out, and I'm glad that I did.

 

[david1978]

I have seen inch per gallon. #of fish per tank. Inch related to surface are and other methods. None work. Sorry. Research and common sense will prevail.

 

[Prest12]

Inch related to surface area

Never heard of that one. I had to look it up. What I was seeing made even less sense than inch per gallon, and that's saying something.

 

[david1978]

Never heard of that one. I had to look it up. What I was seeing made even less sense than inch per gallon, and that's saying something.

Over the years I have seen so many "easy" stocking rules. I have yet to see one that works. Aquadvisor as good as it is is even flawed. Any simple rule even going with small schooling can't work. Fish swim in different areas of the tank. So a tank stocked with 30 neons is much different them a tank with 10 cories, 10 neons and 10 pencil fish. Same number of fish, roughly the same inches and roughly the same bio load.

 

[Kitley]

Just new to this hobby. I have not had acquariums for 15 years now, and a lot has changed.
I purchased a 75 gallon on boxing day, and did a fish in cycle with 6 zebra danios. Added my last batch of fish and snails on Wednesday, and now I have spent two hours watching them. My tank just came alive, all fish seem to be buddies with each other, but any more then the 50 or so fish I have now would be too many. I have neon tetras, black skirted and white skirted tetras, zebra danieos, some dalmation mollies, cories, snails. Some fish are not even an inch, and some are a good 2 inches long. Planning on buying 3 more gold mystery snails and 3 koohlI loaches,, and too sad, but that is it. Only because I do not want them crowded, have had no problems with water parameters. What is next...maybe another tank. These fish are all zooming everywhere and look very happy.

 

[mrsP]

Both. I chose inch per gallon, but where I come from it's actually 1cm of fish per 1 litre of water. That's roughly 1.4 inches per gallon, but in combination with good filteration. Water quality over cm per litre rule here.

 

[angelfishguppie]

Never heard of that one. I had to look it up. What I was seeing made even less sense than inch per gallon, and that's saying something.

What did you find that didn't make sense? Not trying to imply you could not understand it, curious what you did find.

The concept of surface area I've always seen relates to gas exchange, usually focused on oxygenation. It's one reason why a 40 gallon breeder tank is fairly popular in the hobby.

 

[CichlidJynx]

I can keep 100 pencil fish in a 20 gallon no problem but if I followed the inch per gallon I’d be WAY off!

 

[MacZ]

I'm missing a third option.

I go by several other factors:

- temperature
- feeding habits
- social group sizes
- preferred place in the water-column
- preferred water flow

Also in general I tend to understock (biotope aquarist) and over-filter (leftover habit from when I kept Mbuna).

 

[AsleepInYorkshire]

My 12 year old daughters tank is 275 litres which she received for a Christmas present. It's got a Fluval FX4 filter with an inline canister for mechanical filtration. I've removed the mechanical filters from the bottom of the filter and replaced with biological medium. I managed to get 3kg's in. And there is room for another 3kg in the top of the filter if needed. The medium is (and I am not advertising) worth mentioning in my humble opinion. It's Biohome Ultimate. The tank has virtually no nitrates (1ppm). She does a 10-15% water change once a week. I should note that the nitrates never rise above 1ppm We've calculated what fish she can get into the tank based on 1cm/1 litre. They are all smaller fish mostly Tetra's, Corydoras & the like. All the fish are in sufficient "recommended" numbers for their species.

I'm no expert but really have to suggest that you take some time to review the media I've mentioned. As someone who is good at math I get it. The medium simply holds a substantial amount of bacteria and in particular the anaerobic sort is well supported so it gives a complete cycle.

It's very interesting to read everyone's thoughts on this subject too.

AiYn'U

 

[AquaticQueen]

I myself do not use the inch per gallon rule but I know some chain petstores do. If I followed the "inch per gallon rule" I could have a short-bodied flowerhorn in my 10 gallon. Just kidding lol.

 

[CoryBoi]

The inch per gallon rule should be put down. It’s completely rudimentary. Imagine IF an oscar grew to only 10 inches(or imagine another fish that is 10 inches long), the inch per gallon rule says that an Oscar can live in a 10 gallon.
on the other hand you can't stock solely based on filtration. When Stocking you should consider: filtration, size of fish, size of tank, temp, parameters, fish compatibility, and schools.

( I wrote this 2 minutes after you posted teh question but I guess it didn’t post)

 

[Sage Exotics]

The rule is useless. We can all agree it’s flawed (10” fish, 10 gal tank), and even if it’s ok as a loose guide there are better ways for beginners to determine how to stock their tank... the internet! We’re all already the using the best tool we’ve got, here we can speak to experienced keepers who are more than happy to help. There’s no need for flawed, loose, outdated guidelines. Just jump on here and ask! Experience and knowledge are far better than loose “rules”, so why, in the age of the internet, would anyone use the inch per gallon rule?

 

[MacZ]

The rule is useless. We can all agree it’s flawed (10” fish, 10 gal tank), and even if it’s ok as a loose guide there are better ways for beginners to determine how to stock their tank... the internet! We’re all already the using the best tool we’ve got, here we can speak to experienced keepers who are more than happy to help. There’s no need for flawed, loose, outdated guidelines. Just jump on here and ask! Experience and knowledge are far better than loose “rules”, so why, in the age of the internet, would anyone use the inch per gallon rule?

Flaws in your thought: There are still people that use the rule on the internet. Also I've seen so many threads on boards like this one, where people have basically bargained with the people that wanted to help, just to get a "Yeah, you COULD do this..." just as an excuse to still do what they want. Sadly not everyone is willing to ignore an outdated rule that is still to be found on many sites that are there to help inform people and instead ignore those that they asked on forums. Without updating informational websites it will not go away that easily.

 

[CaptAndrews]

While researching, I came across a different perspective on the widely regarded 1 inch per gallon rule. I think it makes a little more sense than the typical/current viewpoint and would love to hear what your thoughts are on it; especially as I'm considering fish to stock my upcoming tank.

Credit to the member 'Guppy' from the Monster Fish forum (see below for a link to the post) who posted this...

The "one inch per gallon" rule

 

[Myyyman]

Wise words, if only everyone would read this. That's a good way of doing it, I would usually just quadriple the amount, e.g, a 6" fish should have 24 gallons. As you can see, this method is flawed and for bigger fish I usually just do the research, but a 6" fish would physically fit in a 24 gallon but not comfortably. Your method is smart.

 

[MacZ]

As far as I can recall consensus here is, you don't have to calculate anything but other factors are more important.

 

[Coradee]

*Threads have been merged*

 

[CaptAndrews]

*Threads have been merged*

Thank you for helping bring the post into conformity. My apologies for not adding it in here and only linking it.

 

[flyinGourami]

Saw this and couldn't help but reply. I really don't like the inch per gallon rule, since it does not take in any factors except that you have fish and your going to put them in water. I also don't really use or "praise" aqua advisor, since it doesn't really take in too many factors either. Yes, a big part is filtration. Your water change schedule is also important, and so are the species of fish you own. Another factor is the temperature and how much you feed the fish. What kind of filtration do you have? Imo another one is the fish's individual personality. By the inch per gallon rule a betta and 5 chili rasboras can fit in a 10 gallon. But what if the betta doesn't tolerate tank mates, or what if you are able to house a betta with 8 chili rasboras without issues? The inch per gallon rule doesn't allow you to keep 20 endlers in a 10 gallon, which in my opinion is fine as long as you have filtration, but allows you to have a common pleco in a 10 gallon(that isn't done growing). All in all, I don't use any websites, I don't listen to random rules, it all comes down to common sense, research and environment. There isn't really a real rule for the amount of fish you can actually stock in the tank and I see a lot of people say blah blah blah can't live in that size aquarium while ignoring the fact that the fish has lived in there fine and normally for 20 years.

 

[eduh]

While researching, I came across a different perspective on the widely regarded 1 inch per gallon rule. I think it makes a little more sense than the typical/current viewpoint and would love to hear what your thoughts are on it; especially as I'm considering fish to stock my upcoming tank.

Credit to the member 'Guppy' from the Monster Fish forum (see below for a link to the post) who posted this...

The "one inch per gallon" rule

Hi, where is this post you mentioned?

 

[CaptAndrews]

Hi, where is this post you mentioned?

Well it was linked, not sure what happened. But here is the link again
.https://www.monsterfishkeepers.com/forums/threads/the-one-inch-per-gallon-rule.88431/

 

[Koenig44]

The inch per gallon rule should be put down. It’s completely rudimentary. Imagine IF an oscar grew to only 10 inches(or imagine another fish that is 10 inches long), the inch per gallon rule says that an Oscar can live in a 10 gallon.
on the other hand you can't stock solely based on filtration. When Stocking you should consider: filtration, size of fish, size of tank, temp, parameters, fish compatibility, and schools.

( I wrote this 2 minutes after you posted teh question but I guess it didn’t post)

I heard this Oscar theory recently....and it really should be the be all end all for this inch per gallon idea. It's so good.