Squeezing Fish In

[Javentule]

I figured this would be as good a place as any..

Basically I am asking, how do you know how many fish to put in a tank?

I've always stood by the inch-per-gallon rule. That is, for every inch of fish you have, you should have a gallon of water. Ideally, you would consider the fish's maximum size. Meaning, if you have a ten gallon tank you'd consider putting:

2 plattys @ 2.5inches a piece
3 blue danios @ 2 inches a piece

Even though the plattys and danios you get may not actually be max size.

I was reading through an aquarium book today that determined the amount of fish in a tank not by gallon, but by surface area. So, they said, for ever inch of fish you have you should have 10 sq inches of surface area. So a 10 gallon tank that's 12 inches wide and 24 inches long give give you ... (I'm bad at maths) x inches of fish.

What method do YOU swear by and why? The surface area method seems to make a LOT more sense to me.

Also, if you have surface/air breathing fish do you count them in your ratio ( as surface area depends on how much oxygen is absorbed into the water for the fish to use)? Also do you adjust for things like more aeration, etc?

 

[newland]

I'm a bit confused by this as it does not take into account the height of the tank.

Anyway 12 * 24 = 288
288sqInch
288/10 = 28.8inch of fish.

 

[sunflower]

I've always used the stocking calculators on the Practical Fishkeeping website and have never had any overstocking problems.

 

[Grey Legion]

hmmm....I guess I may be the odd ball here but I have never used anything when it comes to stocking tanks... mind you I know my limits and try not to over stock
I do push it but never to a point where the tank will fail due to pollution.

I guess I enjoy water chanegs or something

all my tanks seem to do really well, maybe I am lucky or have a eye for healthy good natured fish..I really don't know...boils down to 15 years of trial and error and still enjoying my hobby..

 

[freddyk]

I'm more with Grey. Rules of thumb misguide people and force them to follow rules that don't really exist. Stocking levels depend on the types of fish being kept, the aquarists maintenance routine, filtration on the tank, and personal opinion of what makes a nice tank.

I start slow, stocking my tank gradually. I pay attention to the cleanliness of the water and substrate and the stress levels of the fish. I add more based on how healthy and clean the tank is keeping with my routine, how the fish are getting along, and of course whether I feel I need more of one type or another aesthetically.

You can avoid problems by following safeguarded rules of thumb, but you only really learn through some experimentation.

Keep in mind that height of the tank isn't very important (within reason), surface area makes all the difference. If someone held a gun to my head and forced me to go with a rule of thumb I'd go with a surface area one. Larger surface area means more air exchange, more room for the fish to swim and live (not many fish swim vertically), more territories for anything territorial, and more room to decorate the tank and provide a nice environment for our little wet pets.

 

[Fishist]

I'm more with Grey. Rules of thumb misguide people and force them to follow rules that don't really exist. Stocking levels depend on the types of fish being kept, the aquarists maintenance routine, filtration on the tank, and personal opinion of what makes a nice tank.

I start slow, stocking my tank gradually. I pay attention to the cleanliness of the water and substrate and the stress levels of the fish. I add more based on how healthy and clean the tank is keeping with my routine, how the fish are getting along, and of course whether I feel I need more of one type or another aesthetically.

You can avoid problems by following safeguarded rules of thumb, but you only really learn through some experimentation.

Keep in mind that height of the tank isn't very important (within reason), surface area makes all the difference. If someone held a gun to my head and forced me to go with a rule of thumb I'd go with a surface area one. Larger surface area means more air exchange, more room for the fish to swim and live (not many fish swim vertically), more territories for anything territorial, and more room to decorate the tank and provide a nice environment for our little wet pets.

This is exactly how I stock too.

 

[Tokis-Phoenix]

Apart from what fred has said, there are other things to take into consideration- the one inch of fish per gallon rule is an important rule but should only be loosely applied in some senses and i do not believe it is the most important rule when it comes to stocking; what fish you put in i think is the most important area.

The 2 rules i go by are;
1. one inch of fish per gal to start with to give me an idea of what kind of size fish i can look into- this also will acount for its max size when adult.
2. Type of fish and its needs/requirements;
a. What depth of water it prefers/space to roam in.
b. Whether it is a sociable fish i.e community fish or shoaling fish, predeter or terotorial, nippy or peaceful, and what other types of fish it gets along with with these factors in mind.
b2. Also, if you go for shoaling fish you have to take into consideration how many they prefer to have in a shoal and for what reasons i.e neons need large shoals(8+) to feel secure in and feel less stressed while tiger barbs need to be in large shoals so they can vent their agression out on each other and not other fish in the tank.
b3. Is it a livebearer? livebearers, guppys in particular, are notorious for producing large quantitys of fry on a regular basis so you will need to take into consideration of what to do with the fry and wether you'll have enough extra space for them.
b4. Genders; many fish either don't get along with the opposite/same gender(i.e bettas) or need a special requirement in gender numbers i.e livebearers need to have a 1male per 2/3female minimum to prevent over harrassment
from each other, either that or same gender groups.
c. What ph/water hardness it prefers, wether it needs/prefers salt in the tank and how hardy the fish is.
d. How much waste it produces i.e neons do not produce alot of waste while common/sailfin plecs do.
e. Its living requirements; common/sailfin plecs for example are nocturnal so they need somwhere during the daytime to sleep which doesn't have light shinning on it. Another example is corys, which prefer to have sand based tanks instead of gravel as it doesn't harm/hurt their barbs/whiskers and allows them to go about their buisness of filtering through the bottom of the tank easier.
e2. Enviroment and fish's effect on it; for example large plecs like common and sailfins will knock over/uproot plants when they start getting realy big from just moving around.
Plants will help keep good water quality so if your tank is very stocked these are quite nesarsary to help handle the waste. Plants also offer hiding places for fish which will help keep stress levels amoungst them low too.

With these factors in mind, if you follow them correctly you shouldn't have any problems in stocking.
(i may have forgotton somthing but thats the jist of it)

 

[Jen21]

I always went with the 1 inch rule too. But Ive always wondered if a heavily stocked plant/rock/decoration tank would have the same rule.

 

[Tokis-Phoenix]

I believe you can overstock a bit with heavily planted and decorated tanks, but i would certainly not go overboard in stocking just because of that.
I think with slightly overstocked tanks they're ok as long as the tank can handle the waste being produced and keep good water quality and the fish aern't stressed out and are very compatable with each other.

 

[sinistral]

Hopefully this won't be considered spam, but...

Nothing additional to contribute, but just to comment that freddyk's and Tokis-Phoenix's thoughts on stocking are spot on. Stocking is a complex question that a rule of thumb can't adequately summarize.

Hopefully everyone will get the opportunity to read those two posts.

 

[Javentule]

Well you can see my confusion - going by inch per gallon I can have only 10 inches of fish, but going by the surface area equation I have nearly TRIPLE that. Seems kind of bizarre.

I totally get what you're saying though - we're basically building ecosystems when we set up aquariums and something that complex can't really be set to hard and fast "rules of thumb"

 

[Tokis-Phoenix]

Another example is say you had a 20gal tank, that would mean going by the 1inch of fish per gal rule you could only stock 20neons in it but in fact i suspect you probably fit 30+ no problem due to neons not being high waste producing fish at all and actuallly doing better in large shoals.
On the other hand putting two 10inch common plecs would be overstocking as they need alot of space to move aroung in and are high waste producing fish etc.

 

[dwarfgourami]

To sum up: the one inch rule is there to tell me that I can't have everything I want. But when I want to know what I *can* actually have, I'll come to you, guys!

 

[sylvia]

What I DON'T stand by is the 'inch per gallon GUIDELINE' (it could never be a rule). The reason why?:

2 plattys @ 2.5inches a piece - If these are both female, as platies and other livebearers can store sperm, they can over-stock the tank as it is. If they are a male and female, the male will chase the female constantly and cause her much stress - which could lead to her death. If they are both male, things will usualy work out and you're lucky.
3 blue danios @ 2 inches a piece - Danios should be in groups of at least 5 as they are schooling fish. Besides the stress brought on by being in an inadequately sized shoal that could lead to disease, small groups of danios can often result in the death of low-ranking fish as they will bully each other as they mature. Usualy this isn't too serious but under certain circumstances, if they become particularly agitated, they can kill each other. The reason the could become agitated is because they are in such a small space. The minnimum tank size for most danios is 20 gallons because of their incredibly high activity level.

There you go. Even though the bio-load these fish would produce is ok, the stocking is all wrong.

You just simply need to take a lot more things into consideration. The surface area of the tank, filtration, plants, whether the fish are aggressive, schooling, territorial, like to be kept as pairs, trios, are shy, nippy, prone to being nipped, the area they preffer to spend most time in, their preffered water params and environemnt, the temperature, feeding, whether they are nocturnal, diurnal, active, lazy, slow-moving, boisterous, jumpers, carnivorous, herbivorous, algae-eaters, don't tolerate specific fish, oxygen levels required, current prefferences, etc, etc, all play a role in what fish you can keep with what other fish and in what size tank. Not to mension that 12 neon tetras don't produce the same amount of waste as a 12" oscar! It's fine keeping neons in a 12 gallon but you couldn't keep an oscar in it (assuming the dimensions were large enough for the fish to turn around).