1 inch of fish per gallon? Why?

Question

i have a 29 gal tank with about 25" of fish (i must allow four inches because two of my fish will eventually get 2'' bigger)
anyways, my tank looks empty even with 14 fish in it. Furthermore, i have never ever ever had one single trace of nitrate in my tank. I change the filter once a month and do a water change 1 or 2 times a month. Why am i restricted to 29 inches of fish in my circumstances? Where did this rule come from? Why?

oh yeah and never any sick fish, diseases algea or anything else like that. 4 fish died in the cycling process and thats it.

another thing. I KNOW FISH NEED SPACE but they seem to have plenty of space in my tank. In the fish stores, their tanks are packed with fish..

Answer 1

It's really quite simple. The "rule" was created for people that don't want to bother learning about their fish and those fishes specific needs. That "rule" only truely applies to a typipcally filtered tank of rectangular design in about the same configuration as a 10 gallon and stocked with fish shaped like and with the same requirements of neons and other small tetras. Extremely limited application huh?

That "rule" has been picked up by many chain stores and even some local fish stores as a quick answer to the "how many fish?" question. Never mind that it rarely applies, never mind that it can lead to problems, it's the fast 2 second answer lazy people way to hear.

In short, it's a broken, bogus piece of junk "rule" that is probably the single worst thing to happen to aquarium keeping in the last 50 years. It is completely without merit and should be totally disregarded by anyone willing to learn.

You may or may not be limited to 1" per gallon. Maybe your fish need more room and you are limited to 1/2" per gallon. Maybe you have better filtration and peaceful fish and can keep 2" per gallon. It all depends on your tank, your filter, your willing ness to maintain the tank and the particular fish you are keeping.

Toss the rule and apply common sense to your situation once you have all the details in hand.

Sounds like you are doing an awesome job with your tank, keep up the good work and best of luck!

MM

Answer 2

The rule originated in the 1970's when fish keeping exploaded in America. It was easier for the clearks to just say 1" of fish per gallon since the young people working the stores didn't stick around long enough to learn about the fish. This was easy for the stores as well as the employees to tell the customers and new fish keepers.

Fish in a tank or in a pond go by weight not inches for one main reason, 20 guppies at 1' each would make a 20 gallon tank seem empty. where as 1 20" koi could not live in a 20 gallon tank. Different fish have different requirements when it comes to water.
The main concern here is the filtration and waste removal in the tank. Seasoned fish keepers know the 1" rule really isn't a good rule, but it is a good rule for beginners just learning about fish.

Many schooling fish can be kept in less water for that reason they school. While other fish that are territorial need a little bit more space.

Since I don't know what type of fish you have, as long as your filtration and Dissolved oxygen levels are up, I don't see why you cannot add a few more fish. I have never used the 1" rule in my salt or fresh water tanks.

Answer 3

If you read up on the subject you will come across the guide which states 12sq in of surface area to 1in of fish, the point of limitation on your tank is the simple fact of oxygen more than anything else lets be serious here you have a 29gal tank with 25in of fish if your tank is rectangle and you have only small tetras' you could possibly gent away with 60 fish in there, however, if you read through the question and answers more closely you will find people keeping a gold fish in 1 gallon of water, this fish is the anti filter of the aquarium it some how manages to churn out far more than it eats it requires significantly more oxygen than most fish its size, but by reading up on the requirements of individual fish's needs and looking to the equiptment you use you can increase what you keep the 12sq in per in guide, or if your heart is set on an oscar then you better start slashing that figure to more like 3 sq in per in.
The fact you have no Nitrates before is pretty astounding, as generally even the water out of the tap has some, but would clearly indicate you can add more fish, once you start getting a reading then it shows your reaching capacity for the tank however, remember you need to take into a/c the maximum size of the fish when fully grown.
as for fish shops craming them in thats because the water capacity they have you don't see they generally run there systems from large sumps or basically large empty vats with larger surface areas. think about it if they just had the tank with the fish in there'd be no oxygen and they'd run out of water before they'd sold all the fish. this is another reason why when buying fish you check all the tanks for disease and not just the one your buying from its all the same water.

AJ

Answer 4

I've never followed this rule mainly because I live in a dorm. My brother, who owned a pet store, told me it's to sell larger tanks. Their reasoning is to keep the water clean and provide enough oxygen to go around. However, I have an aerator in a 20 gallon long with 3 malawi cichlids, a kissing Gourami, and a Razorback Musk Turtle. I have quite a large filter; my water is completely balanced and I have never had a problem with disease or fish dying. If you listen to pet store salesman you can buy a lot of things that are not a necessity.

Bottom line- Make sure you have an aerator and a powerful filter...After that-Go get yourself a few more fish.

Answer 5

This rule is a general rule that beginners use to prevent from over stocking a tank. Based on you maintence schedule. I would say that you are near capacity. If you are dedicated enough however to do 50% water changes weekly, you definatly could add a few more fish. You didn't say how long the tank's been set up, but that is another important factor in stocking capabilities. My tank, a 29 gallon, and if I followed the once monthly water change rule, I would be way over stocked. But because I change 50% of my tank volume weekly, my fish couldn't be happier!

Answer 6

It's just a general rule of thumb to go by. Alot depends on the types of fish you have. If you have fish that tend to stay at the top area, then others that hang more along the middle area, then of course the bottom feeders...you can have a few more than the general rule suggests. It's all a matter of space to keep a 'happy' and stress free community tank. And yes, great filtration is a definite must.
Oh, Algae can actually be a good thing! That shows you have great lighting and active bioloads. If you were going to have a planted tank, then you would want algae. I personally LOVE seeing some algae growth on my tanks:-)

Answer 7

I have thirty two fish in my 10 gal. tank and I've had them over a year, I found that the more fish you have you must add more filtration and air to the water, I have a under gravel filter plus two that hang on the back of the tank, I also have two air rock lines that add air circulation to the water, they all look healthy and happy. I change the filters monthly, and clean the tank every three months.

Answer 8

And the pound has more inches of dog per gallon of air than the average house hold so that must mean that you can have that many dogs too, right? The fish in pet stores are being kept in crowded conditions on a temporary basis, not permanent. Your fish are living creatures and need room for their mental well being, not just their physical well being. Please don't crowd them for "looks" and just leave them be with plenty of place to form territories and live peacefully with their neighbors.

Answer 9

If fish had elbows - it would be called 'elbow room'.

In addition to the nitrate problems that can happen in the water - healthy fish need space (like people)

Answer 10

Because, the fish will run out of oxygen if they run out of space. Each inch requires one gallon, because that's how much oxygen that fish needs to survive in.