The "inch Per Gallon" Rule

[FlakeyBiscuit3.14]

I am very new to the aquarium hobby (I have had one 10G with some guppies for a few months now lol) but I have been researching like crazy for my new 29G tank that I will be getting here in a few days. This time I am going to cycle it properly, so I still have quite a bit of time to continue researching and plan out my tank before any fish decisions are made.
 
But this brings me to my current dilemma... the "one inch per gallon of tank" rule.
 
Now, I know that this rule is general and does not apply to the behavior of the fish. Such as you should not keep a full grown 6" rainbow shark in a 10G even though it will technically fit. And just because you can fit 1 oscar, 2 ciclids, and 5 guppies in a tank by this rule does not mean those fish should EVER go together.
 
My problem is that, by this rule, I will be able to keep far less fish than I had hoped.
 
For example, I really want cory cats and I was hoping for one schooling species too. But if I get 6 julii cories, and 8 bloodfin tetras, both 2 inches full grown, that already puts me at 28 inches for my 29G tank! And beyond that, once the substrate and decor is in the tank, won't it be considered less than 29G? Because there is less swimming space?
 
If I were to stock the tank exactly as I wanted it, with no regard to this rule, I would probably put 6 pygmy corries, 4 julii cories, 8 bloodfin tetras, and 5 male guppies (from my 10G). This totals to full grown 40 inches. Obviously 40 is quite a bit over 29. Is this a ridiculous over-stocking? I know that experienced fish keepers can keep overstocked tanks and just do more frequent water changes, but as already stated, I am no where near experienced in this hobby yet.
 
Do I just need to suck it up and keep fewer fish? Or does the type of fish (schooling vs territorial, large vs small bioload) make a large enough difference that I could squeeze more than 29 inches into my 29G?

Thanks in advance for you help

 

[noobgamers]

yes that would work i would actually recomend geting 3 more guppies and 2 more julli corydoras i would also say to addd some sort of algae eater (read into it more types than you think and they all have different uses e.g sae east filamentous and bn pleco eats green spot and others) .
i see where your coming from with 6 and 4 corydoras but dwarf corydoras act like corys half th etime and tetra the other half very interesting to watch .
the inch per gallon rule isnt very effective only about half tank stockings work with it exc the ridiculous ones like 1 29 inch arowana to a 29 gallon so it will be better to ask here or use a stocking calculator

 

[daizeUK]

 I think the inch per gallon rule is an excellent guide when you're first setting up a tank but it does not mean you can never add more fish.  I would give a tank several months to stabilise and mature and then I would start graduating from the inch-per-gallon towards the cm-per-litre rule which is far less restrictive.
 
Also what figure are you using as the adult size of male guppies?  Remember they are much smaller than females.

 

[FlakeyBiscuit3.14]

noobgamers- Okay, thank you!! I'm surprised you think I can fit more than that, but that's good news for me Gives me more options.
Do you happen to know of a good stocking calculator? I'll try googling it too.

daizeUK- Yes, I figured I would add slowly...but I am by nature a planner For the guppies I was using 2in. Is that more for the females?

This is great news for me guys!! Thanks so much! I am feeling so free right now lol

 

[daizeUK]

I would use 1.5 inches per male guppy and 2.5 inches for the females, at most.

 

[noobgamers]

noobgamers- Okay, thank you!! I'm surprised you think I can fit more than that, but that's good news for me

Gives me more options.
Do you happen to know of a good stocking calculator? I'll try googling it too.

daizeUK- Yes, I figured I would add slowly...but I am by nature a planner

For the guppies I was using 2in. Is that more for the females?

This is great news for me guys!! Thanks so much! I am feeling so free right now lol

for stocking calculator use [edit] single r it filters it out when i do single r

 

[fluttermoth]

There's a very good reason why our forum filters out the name of that site, noobgamers; please don't bypass it.

All stocking calculators are a pretty poor way to go about things, but that is one of the worst ones; we've seen some terrible stockings that have been fine, according t to it.

 

[FlakeyBiscuit3.14]

Does that mean that I should disregard the high stocking suggestion? I would like to have more fish, but I'd much rather the fish I do have are happy and healthy.

 

[fluttermoth]

As long as the fish you're intending to keep are small (less than three inches or so, adult size), and you make sure your water change regimen is up to scratch, you can certainly go for the higher stocking levels. Just build up to it gradually as your tank matures, if your water tests come back as they should; watch out for the nitrate climbing.

 

[FlakeyBiscuit3.14]

Well, I do intend on meeting those two requirements!
 
I suppose now I will just have to wait for my tank to cycle. Maybe I'll start researching plants next.....
 
Thanks again for all advice! 

 

[Chad]

I feel the "inch per gallon rule" is a terrible thing. It's too vague and can lead to problems. For example, I can't keep a 10 inch long oscar in a 10 gallon tank, or even a 20 gallon tank, or even a 30 gallon tank. That's just one example of many that demonstrate that the "rule" doesn't work.
 
I consider all of the below when choosing a fish. 

1. max fish size
2. temperament
3. type of food
4. quantity of food
5. metabolism
6. fish compatibility
7. coral compatibility (for marine tanks)
8. invert compatibility
9. substrate requirements
10. swimming requirements
11. swimming ability
12. flow requirements
13. sensitivity to changes in parameters
14. sensitivity to water quality issues
15. sleeping habits
16. rock work requirements
17. lighting preference
18. body shape (deep keeled vs shallow)
19. territorial requirements (I can only keep 1 male clown goby in my 210 gallon tank and that fish is tiny).
20. escape and jumping potential
21. temperature requirements (temperate vs tropical also temp range and how temp affects metabolism)
22. growth rate

Though this seems like quite a few things to consider they are usually found quite on the Internet and in some cases just common sense. Generally speaking I can discover in 5 minutes or less if a fish will work in my system or not. 
 
I advocate far more conscientious fishkeeping than the 1 inch rule allows for. 

 

[daizeUK]

That's interesting that water hardness and pH tolerance are not on your list, Chad; those are some of the first things I look at.
 
I think the major thing missing from the OP's context is - can my tank's biological filtration cope with the bioload of this fish (or shoal of fish)?  That's not so easy to determine and where something like the inch-per-gallon rule, with all its admitted flaws, comes in handy for a newbie.  Agreed it only helps for small fish though, not large ones!

 

[Chad]

I should break it apart but #13 and #14 "sensitivity to water quality issues" and "sensitivity to changes in parameters" are intended to cover issues of pH, salinity for marine animals, etc. In its current form the list is a reminder to me but I intend on fleshing it out someday. 
 
The point is to demonstrate that there is much more to selecting livestock than "I have one gallon, so I can have one inch".

 

[Freedom]

If I were to stock the tank exactly as I wanted it, with no regard to this rule, I would probably put 6 pygmy corries, 4 julii cories, 8 bloodfin tetras, and 5 male guppies (from my 10G). 

One good site to get info on each variety of fish is Seriously Fish dot com.  You will quickly learn the Latin names of each as that is how they show up!
 
Then in going over things, you start to fine tune your selection.  I started thinking bloodfin tetras, then saw rummy nose tetras and fell in love, he heee.  So I have a nice school of 10 of those. 

 

[daizeUK]

The point is to demonstrate that there is much more to selecting livestock than "I have one gallon, so I can have one inch".

 
Absolutely but I would view it more as something after you have done your research and selected suitable species, then it helps to give a rough guide on whether your tank is capable of accommodating them.