Stocking level?

Question

When you're calculating how many inches of fish can fit in an aquarium, do you use fish length as measured with or without the tail?

Answer 1

I don't use either, one of my aquarium is way overstocked, but I can do this because I do water changes religiously (once a week) I have 80 dwarf cichlids in a 55 gallon aquarium, my ammonia and nitrite levels are at zero, and my nitrates are at 20 ppm If you commit to changing your water religiously and checking your levels peiodically it doesn't matter to much how you measure them. I should not have more than 30 dwarf cichlids in my tank, but obviously they are not stressed because I just noticed about10 more fry this morning (not included in the 80). Also these are agressive fish but because of my rock formations in my tank these fish have numerous hiding spots, so actually with all the rock in my aquarium I probably have only 45 gallons of water in the aquarium

Answer 2

None of the above. The rule doesn't apply to any fish other than a neon tetra.

Think about it. You have 10 one-inch neon tetras and 1 ten-inch goldfish. Do these produce the same amount of waste? The tetras would be fine in a 10 gallon tank, but a goldfish that size couldn't turn around or swim - he'd just hover in place.

The "rule" doesn't take into account things like your filtration - an airstone vs. a hang-on or canister filter (or a wet/dry filter for a big tank). Or how often you do water changes or how much water you change.

It also doesn't consider the tank shape. A 20 gallon tank can be an "extra high" which has the same bottom area as a 10 gallon (20x10 inches), or it can be a 20 long (30x 12). Think about that 10" goldfish - you might be able to keep it in the second tank, but not the first. The dimensions are even more important in terms if the surface area of the water - where the oxygen and carbon dioxide are exchanged. The more surface area, the faster the exchange occurs, so with a lower, wider tank you can keep a few more fish than in a taller, narrower one, even though both hold the same amount of water.

A last thing to consider is the aggression level and activity level of the fish involved. If a species is aggressive to others, you won't be able to keep many of the same kind without constant fishting for territory. And active swimmers will need more swimming space than fish that just hang around in one place most of the time.

So forget you ever heard about the "one inch rule" - no such thing exists that will work!

So how do you go about figuring out how many fish you can keep in your tank? I'm going to suggest a couple of links that can help you out, and take all the stuff I've talked about into consideration. It will pick up on any potential problems, not only in how many fish, but the kinds you want to keep together. Give these a try: http://www.tropicalresources.net/phpBB2/templates/BMan1Blue/Stocking.htm
http://www.thinkfish.co.uk/community.html - you need to register to use this website.

Answer 3

Okay..first off, the measurement of the fish is without the tail as an adult. Second, that entire school of thought was debunked a long time ago.
A 3" betta can live quite comfortably in a 1 gallon tank with a filter and heater. A 12" Oscar can NOT live in a 10 gallon tank.
Stocking depends on the fish you choose to put in it. A goldfish requires a 10 gallon tank each. An Oscar requires a 55 gallon tank. None of these fit that rule of thumb.
Things to take into consideration are total body size and biological waste output. The messier the fish: cichlids, goldfish...the more gallons required.
Another thing to think about is aggression levels. While you can toss a whole lot of peaceful community type fish into a tank, cichlids, knifefish, etc need more space to establish territories.
Lastly, is the length of the fish itself. For a very large fish like an Oscar, it needs at least 1 1/2 x its adult size in width to turn around and at least 4 x its length to swim.
What type of fish are you looking to get? There are minimum requirements for happy, healthy fish for each individual species.

Answer 4

Also, when calculating, you need to use the length the fish will be at maturity, not the size it is when it is a baby. If you research a certain breed and it says it will grow to be 4-5 inches, estimate using 5 inches. Always use the higher estimate.

Additional info: To the guy who is so proud that his tank is so overstocked, you should be embarrassed to admit that. Those overcrowded conditions are horrible, I don't care how clean you say your water is. People like you should NOT be giving advice to beginning fish enthusiasts. That's a disaster waiting to happen.

Answer 5

The number of inches per gallon rule is still vague no matter how you look at it. I went to this one website http://www.elmersaquarium.com and their chart read a bit differently:

10 gallon - 08 to 12 fish
20 gallon - 12 to 15 fish
30 gallon - 15 to 20 fish
55 gallon - 20 to 30 fish

Take note that the quantity of fish per gallon tank is based on the size of a Swordtail which measures up to 4" long!

Answer 6

Definitely use the tail, unless they are tail-less fish. Your math would be off depending on how many fish or how big the fish are. Maybe only one off but in math it is right or wrong. Always remember the tail! good luck

Answer 7

You take the fish's length, and its thickness.

Answer 8

with a tail
a tail is also a part of a fish and takes up a little bit of space