How Do U Work Out How Many Fish You Can Have In Your Tank?

[Michelleuk]

how do u work out how many fish you can have in your tank??

 

[Torrean]

for beginners 1" of adult fish per gallon is a good rule. however this is relative. You couldn't keep a 3 inch gourami in a 3 gallon tank.

It's hard to define exactly how many fish you can keep because there are so many types.

 

[MasterP]

generally you can stick to this rule but can get a little over what the limit is if you keep smaller fish.

 

[wodesorel]

I've always done research for each particular species that I'm interested in. Most of the time you can find out what their true inch per gallon rule is (I know black kuhlis can be calculated at 1.5 inches even though they can reach 4 inches - Most species are double to triple the inch per gallon rule). You can also find the requirements of each species in regards to tank size - what size tank they need to move around in comfortably, which can't be calculated by the inch per gallon rule. The research is also helpful in finding out if they need hiding places/plants in the tank, the temperature they're best kept at, the food that they need (some will only accept live/frozen), what species they can or can't be mixed with, and what their true grown size really is, what a good target is for water parameters (nitrate and pH and hardness).

I started out just buying fish without looking into what they really needed and made some serious mistakes in the past. Now I know to research and research and research and really think about what I'm going to buy before I go to the stores.

 

[juicebox]

also, messier fish like goldfish, common plecos (which are not beginner fish anyway), and platys need bigger tanks despite however many inches they grow because they poop a lot.

 

[Bignose]

Here is a reply I made in an old thread:

Firstly, the amount of waste a fish will produce is primarily based upon the mass/volume of the fish. Consider that a 4 inch streamlined, torpedo-shaped rasbora will not be producing the same amount of waste as a rotund, beer-bellied 4 inch molly who is in a late-term pregnancy.

Secondly, as noted in the 1st post, the one inch per gallon rule becomes very silly in the limit of large fish. 20 one inch fish (like small tetras) can be very happy in a 20 gal tank, but obviously one 20 inch fish will not.

Thirdly, the species of fish enters into consideration. Fish from rapidly moving, highly oxygenated waters will require more water per fish than fish from slow moving stagnant ponds. This is where research becomes necessary. Also, some fish are very territorial. A 5 inch fish may claim much more than 5 gallons as its own personal space.

Finally, the fishkeeper's caretaking habits can change the balance as well. If you commit to increased water changes and caretaking, and you 'over-filter' your tank, you can get away with overstocking. But this is only recommended for the more experienced fishkeepers. Likewise, if you want to be lazier, you can plant your tank to help process the fishs' pollution but that requires an aquatic green thumb so-to-say. There are whole other issues for keeping aquatic plants alive.

Many, many factors that "one inch per gallon" cannot take into account. It is just a starting point, and a good place to help newer fishkeepers not run out and purchase as many fish as can fit in a small tank. To be completely accurate, all the above factors, and maybe several I have not even considered, need to be taken into account. Whatever the result will be, it will not be as catchy as "one inch per gallon" which again, is only a starting point.

So the point is, and people have posted above, you have to research the fish you want to keep, and you have to know your own abilities.

 

[fish_fetish65]

Generally, you should abide by the inch per gallon rule, which states that for each inch of fish you have in your tank (using the fish’s maximum potential size), you should have one gallon. For instance, a neon tetra’s maximum potential size is 1.5 inches. Therefore, one neon tetra would theoretically need a 1.5-gallon tank (minimum) to live. For larger species of fish (four or more inches), it is best to double, or even triple, the tank size suggested by the inch per gallon rule.

 

[Lord Zogat]

how do u work out how many fish you can have in your tank??

Take the total Gallons of your tank = G
Take the total Gallons of your filter Capacity = F
The Realitive humidity of the room = H

Ok ok, so you pump it all into the following equation, where X is the number of fish

x = [G / (squareroot of F)] / H + 2

Ok, maybe the 1 inch of adult fish per gallon is better eh...lol sorry in a wierd mood.

What the heck would that equal anyways.....

G = 10 and 20 (two bridged tanks) = 31 Gallons, (bridge probably holds 1 gallon easy)
F = 55 Gallons (Two filters)
H = how the hell would I know? Relative Humidity - - Uh yah lets go with 57.8% or .578

ok, ok,

x = (31/ square root of 55)/ .578 +2
x = (31/ 7.42)/.578 +2
x = 4.2/.578 + 2
x = 9 fish

Hmmmmmm

 

[Lord Zogat]

lol. everyone stunned at my reply...no comments...

 

[fish_fetish65]

... never been good at math, but that was a nice creative reply! *claps*

 

[cs091]

how do u work out how many fish you can have in your tank??

Take the total Gallons of your tank = G
Take the total Gallons of your filter Capacity = F
The Realitive humidity of the room = H

Ok ok, so you pump it all into the following equation, where X is the number of fish

x = [G / (squareroot of F)] / H + 2

I hope you're just joking cause this doesn't make sense.

In your equation, increasing the filter capacity would DECREASE the number of fish you could have.

 

[Griz]

how do u work out how many fish you can have in your tank??

First, ignore all the so-called "rules". There are so many variables to consider that any "rule" will lead you into trouble. The best approach is to research the fish you want to keep. Find out how much space they need, what size group they do best in, m/f ratios, etc. Territortial issues are more important than anything for many species, especially cichlids. Species tanks are a bit easier to figure out. For communities, research what tankmates will be compatable and what their needs are. Stick to the tried and true combinations. Keeping fish from the same biotpe is usually the best strategy although other combinations can work if done carefully and with some thought. Do the research and post your questions here so that you can get advice from people experienced with the fish you want to keep. There are no shortcuts!

 

[b.c.f.c]

2bh do all the research possible, and then use your common sense .
the inche per gal rule is probly the best rule but as i say its all common sense and research.

 

[Tolak]

There are no rules, only guidelines. Do your research, and understock from the start. The 1" per gallon thing applies only to slim bodied fish that grow no larger than 3". Start with half this, get used to doing water changes of a quantity & frequency that will keep the tank looking clean, and keep your nitrates to a reasonable level.

Stocking a tank is half science. The other half is understanding fish behavior & such, you get a sense about it with time. The other half is more art than anything.