Inches of fish per tank equasion??

Question

20 gallon
I think its 30x12x16 somethin like that.

How many inches of fish?!

Answer 1

The rule you'll most often hear about is an inch of fish per gallon of water. However, full bodied fish such as Goldfish, require far more space than that. You must also take into account the shape of the tank, as the air exchange happens at the surface of the water. 10 gallons is not a lot of real estate, so you won't be able to keep too many fish in that aquarium. I'd stick to small, slim bodied fish. A half dozen schooling fish, such as neon tetras would be lovely, with a small bottom dwelling fish or two. Or consider keeping a small school of Danios and a couple of barbs. There are many options, just take care to avoid fish that reach an adult size larger than inch or two. As a general yardstick for normal situations, the one-inch rule works adequately and is very easy to calculate. If using it, always use net gallons of water, and take into account the adult size as well as the shape of the fish. If the aquarium is a non-standard size, the surface area rule will work better than the one-inch rule. In either case, always do your homework first, and err on the side of going under the limit rather than over. Also do not fully stock the tank all at one time. No more than 25% of the total volume of fish should be introduced at one time. Fish wastes, which are toxic, are eliminated by colonies of beneficial bacteria. Those bacterial colonies need time to adjust to changes in the bio-load. By introducing fish a few at a time, the bacterial colonies have sufficient time to grow and take care of the toxins produced by the fish waste. Good Luck!

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

You can have 1 inch of fish per gallon of water in your tank. so for a 20 gallon tank you can have 20, 1 inch fish, 10, 2 inch fish and so on.

Answer 4

the fish equation is not based on how deep it is, but the square inches of the surface. Also, fish can be very tiny, meaning more fish, or huge, like 6-7 inches, meaning just a few fish. You could safely put around 15 small fish in there. the surface area is where the oxygen comes in which the fish need. you can help them by putting air bubblers into the tank as well.

Answer 5

ugh the fish per gallon thing is just a guideline -- not a rule. you can easily double thin fish like white cloud mountain minnows but you could only keep 1 or 2 goldfish. you don't want to keep a 20" arrowana.

i have a 20 gallon with 1 betta, 2 pearl gouramis, 4 sunset honey gouramis, 7 raspboras. everyone is happy. sometimes a iget a bag of ghost shrimp. they last a couple months and then all disappear.

Answer 6

20 inches of fish. 1 gallon of water per inch of fish. But make sure you figure it for the full grown length of the fish before you buy them. They grow really fast. So if you buy 20 inches of small baby fish and put them in there they will soon be overcrowded. :)

Answer 7

Forget the 1 inch per gallon rule, it's completely bullshit

you can put as little as 1 fish, but as much as 25 fish in your tank, it all depends of the species and their needs

Just an example
if an oscar gets to be 14 inch, you could easliey keep him in a 15 gallon right? BUT no, that's not true, he needs at least a 75 gallon to be happy

So, there goes your 1 inch per gallon rule


Give me info on what you would like to have and i can tell you how many



Hope that helps
Good luck

Answer 8

The general rule of thumb is one inch of fish per gallon of water, so in your case, you could have 20 inches of fish.

Answer 9

One inch of fish per gallon of water. This however really depends on your filtration system.

Answer 10

I've been told, it's one inch (of fish) per gallon of water.