# Is there a rule of thumb for stocking levels with small schooling fish?



## BryceM (Nov 6, 2005)

Bunbuku said:


> What your rule of thumb for the fauna:tank size, assuming we are talking about small schooling fish? Do the shrimp carry the same "weight" as fish when it comes to the bioload?


Would anyone like to elaborate?

Personally, I consider the mass and activity level of fish when trying to determine acceptable stocking levels. How many celestial pearl danios does it take to weigh as much as a full-grown angelfish? 100? Maybe more? The little danios are perhaps a bit more active so I wouldn't get too carried away.

In a 20g aquarium you can easily keep 3 or 4 dozen *small* schoolers. If you use bigger fish, like rummynose or harlequins, I'd limit it to 2 dozen or so.

That's just me though.

You could keep hundreds of the little shrimp like CRS's. Amanos probably count the same as a rummynose, at least when full-grown.


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## new2plnts (Jul 8, 2008)

Do you think the amount of filtration may play a part in this. 
if you have a heavily filtered tank I would think you could have more than usual and vice versa. I asked about how many White clouds in a 10 Gal and someone said 10-15. would you consider these bigger fish or no. I am going to have RCS in the tank as well


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## DonaldmBoyer (Aug 18, 2005)

I think that a lot has to do with filtration and plant load. The more filtration and plants, the more fish and inverts you can safely keep.

In general, I keep my tanks filtered twice as much as "recommended" and follow the "1 inch fish per gallon of volume" rule. For me, that would be 200 inch long fish. However, I do keep it heavily planted and have double the filtration than I really need, so I figure that I could keep 300 fish in there, if I wanted to, or 200 medium size fish (like rummys), or 100 larger fish (like angels). Or, I could safely keep 1000 RCS's.

Also, if you have a tank crammed full of slow growing plants (like anubias or mosses), these plants are going to utilize the wastes produced by fish as quickly either. If you have fast growing plants (like hygros) jammed into your tank, you could likely add more fish as these plants will absorb and biochemically change the wastes and produce for them to consume (or harmless by products).

In addition, if you add more filtration, you would want to utilize carbon or some other biomedia to produce extra "volumes" of bacteria to keep the water clean. I do not use carbon, so I would want to watch how many fish I put into my aquarium, even though I have it heavily planted and have more filtration than I need.

Aquarium size, too, counts. My current tank has a base of 4 feet by 4 feet with an average substrate depth of about 5 inches; in this fashion, I know that my bacterial count in my substrate should be pretty high (which is why I don't use carbon in my filtration). However, if you are dealing with a tank with a smaller footprint of 4 feet by 2 feet, you are dealing with half the volume of my tank (in comparison), so your bacterial count theoretically reasons will be half of what I have. This is also another consideration when it comes to stocking a tank.

There are likely many other factors to consider as well. Is this a high tech tank with a ton of CO2 and ferts added to it? Is this a NPT with no CO2 or ferts? Do you have high light to make the plants grow at a faster rate thereby increasing the nutrient uptake? Do you have substrate or is it bare bottom for breeding? On that note, would you plan on allowing whatever fish or inverts in there to spawn and try to rear fry/shrimplets, or would you remove the fry to a different tank?

I would think that these would all be factors in deciding, ultimately, how many fish you would wish to try to add.


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## BryceM (Nov 6, 2005)

Oh, I wouldn't recommend 100 angels in anything below one or two thousand gallons.

1 angelfish does not equal 4 or even a dozen small tetras. Look at the mass of the fish.


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## Sunstar (Sep 17, 2008)

that sounds rather logical. The mass being the factor rather than the inchage. 

I just wonder, although at the moment they are in it for Quarentine isolation as well as trying to fatten them up...they were hungry looking, I put my celestial pearl danio in a quarter gallon vase. they may have a few shrimp companions who refused to be evicted. They are very tiny fish....the inch per gallon rule applies then they are over crowded. However they don't seem to move all that much save to hide in the plants. (It is my male and female future breeding pair)


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## Cliff Mayes (Jan 29, 2007)

Compare a spawning pair of Angels with a non spawning pair. The space required for one is quite different than the other. Space required is more than just mass, although that is a consideration.

There is no working rule for stocking unfortunately. The inch per gallon rule may have made sense a long time ago but the variety of species and sizes available to todays aquarist is so broad as to defy description let alone easily lend it self to nice rules. I too have a tendency to keep smaller, well behaved , species in my non Goldfish tanks but a lot of folks do not, so we need to be very careful about supporting "rules" for others.

I have always been in favor of overfiltering. It is alway better to have too much rather than too little.
The Bacteria cultures only exist in relation to what is made available to feed them but who knows how large the total Bacteria mass can be if given enough room to grow and too how much do colonies stifle themselves in a given spot over time if allowed to grow and prosper.


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## bartoli (May 8, 2006)

DonaldmBoyer said:


> In general, I keep my tanks filtered twice as much as "recommended" and follow the "1 inch fish per gallon of volume" rule. For me, that would be 200 inch long fish. However, I do keep it heavily planted and have double the filtration than I really need, so I figure that I could keep 300 fish in there, if I wanted to, or 200 medium size fish (like rummys), or 100 larger fish (like angels).


200 rummys in a 20g? How about the psychological space for individual fishes?


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## jargonchipmunk (Oct 25, 2008)

I believe that number was for a 200 gallon tank, as he stated the inch per gallon rule just before.


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## JanS (Apr 14, 2004)

When it comes to stocking the smaller schooling fish in a decent size tank, it usually comes down to how many can you afford....


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## Afyounie (Aug 10, 2007)

I agree with JanS. I'm usually stopped by how much I'm willing to spend, and usually the LFS near me only stocks about 20 or less of each schooling fish at a time.


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## Bunbuku (Feb 10, 2008)

Some of NASH folks here do not stock their planted tanks heavily at all. i understand that part of the rationale is to reduce chances of algae. 

My previous 60 P scape (RIP) had about 2 dozen embers, 6 oto's, massive numbers of tiger shrimp (because they reproduced) and 12 Amanos. The filter was rated for a tank 3 times its size. 

Though I have not gotten around to stocking my rescape yet, I think I will go light with the equivalent of ~8 cardinals or small rasboras, 3-4 oto's, 10 Amanos. 

One interesting note, when I tallied up the cost of the plants I got for my 60P rescape, it was as if I got 6 dozen cardinals! Insanity! Willing to spend more for plants than fish :clock:


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## Cavan Allen (Jul 22, 2004)

I think that it also has to do with how many are in there before it looks overcrowded and distracts from the plants. To me it seems that you'd really have to have quite a few in a well-run tank to get to that point.


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## xpirtdesign (Dec 5, 2008)

i dont go more than 1 fish per gallon for my tetras


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## overboard (Mar 11, 2008)

I have made up these rules for planted tanks: 

1. Shrimp don't count.
2. Otos don't count. Neither do very small cories that are cute.
3. If the snails start literally piling on top of each other, they need to be factored in.
4. Any fish that you can't catch doesn't count, because you don't really intend it to still be there.

My most crowded tank is a 20 long, very heavily planted. It has three big kribs, a pair plus another female that hides all the time. I have tried and failed to catch her, so I invoke rule #4. Same goes for a pencil fish, left over from a school of them that were an attempt at dither fish (I moved the rest out). There are two otos and two pygmy cories, which don't count under rule #2. There are eight zebra danios (which are awesome dither fish). The danio fry don't count, because they are food for everyone else. So that means there are only ten fish in the tank, 12" of danios and 8" of kribs... 20", 20 gallons, no problem here! 

Anyone else's tank need rationalizing?


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