Re: Is the load too much?

[Marcus Fox]

"Cplus" > wrote in message
e.rogers.com...
> The two remaining mollies (had another black one die on me this morning)
> that I had in 20g tank I moved to my daughter's 10 gallon tank (because
the
> 20g is high in nitrites still). I moved them because their back fin (not
> sure of the specific name) was starting to curl in (they're lyretail
> mollies).
>
>
> The 10G tank already houses :
> 1 guppy
> 2 angels
> 5 tetras (2 glow light, 3 pristella)
> a pleco
>
> and now I've added the mollies. Will that be too big of a load? It
doesn't
> seem like it when I write it down but it seems busy in the tank.

I thought a good rule of thumb was one inch of fish per square inch of
surface. And I thought angelfish ate tetras?

Marcus

[Jim Brown]

Marcus Fox > wrote in message
...
>
> "Cplus" > wrote in message
> e.rogers.com...
> > The two remaining mollies (had another black one die on me this morning)
> > that I had in 20g tank I moved to my daughter's 10 gallon tank (because
> the
> > 20g is high in nitrites still). I moved them because their back fin
(not
> > sure of the specific name) was starting to curl in (they're lyretail
> > mollies).
> >
> >
> > The 10G tank already houses :
> > 1 guppy
> > 2 angels
> > 5 tetras (2 glow light, 3 pristella)
> > a pleco
> >
> > and now I've added the mollies. Will that be too big of a load? It
> doesn't
> > seem like it when I write it down but it seems busy in the tank.
>
> I thought a good rule of thumb was one inch of fish per square inch of
> surface. And I thought angelfish ate tetras?
>
> Marcus
>
>

One fairly common standard (but not fully accurate) is one inch of fish per
gallon of water. That equates to about one inch of fish for every twenty
square inches of surface.
Using a standard 15 gallon tank with a surface of 12" x 24", that's 288
square inches, or more than twenty feet of fish using your rule.
Not all angels eat all tetras. A better statement would be almost all fish
will eat fish small enough to fit in their mouth.

Jim

[Marcus Fox]

"Jim Brown" > wrote in message
.. .
>
> Marcus Fox > wrote in
message
> ...
> >
> > "Cplus" > wrote in message
> > e.rogers.com...
> > > The two remaining mollies (had another black one die on me this
morning)
> > > that I had in 20g tank I moved to my daughter's 10 gallon tank
(because
> > the
> > > 20g is high in nitrites still). I moved them because their back fin
> (not
> > > sure of the specific name) was starting to curl in (they're lyretail
> > > mollies).
> > >
> > >
> > > The 10G tank already houses :
> > > 1 guppy
> > > 2 angels
> > > 5 tetras (2 glow light, 3 pristella)
> > > a pleco
> > >
> > > and now I've added the mollies. Will that be too big of a load? It
> > doesn't
> > > seem like it when I write it down but it seems busy in the tank.
> >
> > I thought a good rule of thumb was one inch of fish per square inch of
> > surface. And I thought angelfish ate tetras?
> >
> > Marcus
> >
> >
>
> One fairly common standard (but not fully accurate) is one inch of fish
per
> gallon of water. That equates to about one inch of fish for every twenty
> square inches of surface.
> Using a standard 15 gallon tank with a surface of 12" x 24", that's 288
> square inches, or more than twenty feet of fish using your rule.
> Not all angels eat all tetras. A better statement would be almost all
fish
> will eat fish small enough to fit in their mouth.

Yes, I was a bit confused when I wrote that. But I find the 1 inch per
gallon rule innacurate, particularly as a 1 inch fish weighs about 1/8th of
a 2 inch fish of the same shape, so it clearly uses more like 1/8th of the
oxygen and produces a corresponding amount of waste products.

This table should be a bit more accurate, therefore. (It is not mine)

Size No. Per cm2 of surface Approx.
cm2 per fish

1 400
2.5
2 110
9
3 50
20
4 25
40
5 12
80
6 8
125
8 5
200
10 2
500
12 1
750
15 1
1100

HTH

Marcus

[Jim Brown]

Marcus Fox > wrote in message
...
>
> "Jim Brown" > wrote in message
> .. .
> >
> > Marcus Fox > wrote in
> message
> > ...
> > >
> > > "Cplus" > wrote in message
> > > e.rogers.com...
> > > > The two remaining mollies (had another black one die on me this
> morning)
> > > > that I had in 20g tank I moved to my daughter's 10 gallon tank
> (because
> > > the
> > > > 20g is high in nitrites still). I moved them because their back fin
> > (not
> > > > sure of the specific name) was starting to curl in (they're lyretail
> > > > mollies).
> > > >
> > > >
> > > > The 10G tank already houses :
> > > > 1 guppy
> > > > 2 angels
> > > > 5 tetras (2 glow light, 3 pristella)
> > > > a pleco
> > > >
> > > > and now I've added the mollies. Will that be too big of a load? It
> > > doesn't
> > > > seem like it when I write it down but it seems busy in the tank.
> > >
> > > I thought a good rule of thumb was one inch of fish per square inch of
> > > surface. And I thought angelfish ate tetras?
> > >
> > > Marcus
> > >
> > >
> >
> > One fairly common standard (but not fully accurate) is one inch of fish
> per
> > gallon of water. That equates to about one inch of fish for every
twenty
> > square inches of surface.
> > Using a standard 15 gallon tank with a surface of 12" x 24", that's 288
> > square inches, or more than twenty feet of fish using your rule.
> > Not all angels eat all tetras. A better statement would be almost all
> fish
> > will eat fish small enough to fit in their mouth.
>
> Yes, I was a bit confused when I wrote that. But I find the 1 inch per
> gallon rule innacurate, particularly as a 1 inch fish weighs about 1/8th
of
> a 2 inch fish of the same shape, so it clearly uses more like 1/8th of the
> oxygen and produces a corresponding amount of waste products.
>
> This table should be a bit more accurate, therefore. (It is not mine)
>
> Size No. Per cm2 of surface Approx.
> cm2 per fish
>
> 1 400
> 2.5
> 2 110
> 9
> 3 50
> 20
> 4 25
> 40
> 5 12
> 80
> 6 8
> 125
> 8 5
> 200
> 10 2
> 500
> 12 1
> 750
> 15 1
> 1100
>
> HTH
>
> Marcus
>
>

You are right in that fish mass has more of an impact than fish length.
Unfortunately, while mass is definitely better but harder to estimate, there
are also factors such as activity, age, aquarium parameters, and types of
food.
Your chart still needs some work. The first column sets out square cm's of
fish but it might be better to set out cubic cm's. The second column sets
out square cm's, and how many one inch fish could be stocked in an aquarium
with a (roughly converted) one inch square surface.
You can try but I don't think anyone will deveope anything better than a
rough guide for 'bread and butter' fish from the LFS. Far better to learn
from the experience of others and add that to one's own observations.

Jim

[NetMax]

"Marcus Fox" > wrote in
message ...
>
> "Jim Brown" > wrote in message
> .. .
> >
> > Marcus Fox > wrote in
> message
> > ...
> > >
> > > "Jim Brown" > wrote in message
> > > .. .
> > > >
> > > > Marcus Fox > wrote
in
> > > message
> > > > ...
> > > > >
> > > > > "Cplus" > wrote in message
> > > > >
e.rogers.com...
> > > > > > The two remaining mollies (had another black one die on me
this
> > > morning)
> > > > > > that I had in 20g tank I moved to my daughter's 10 gallon
tank
> > > (because
> > > > > the
> > > > > > 20g is high in nitrites still). I moved them because their
back
> fin
> > > > (not
> > > > > > sure of the specific name) was starting to curl in (they're
> lyretail
> > > > > > mollies).
> > > > > >
> > > > > >
> > > > > > The 10G tank already houses :
> > > > > > 1 guppy
> > > > > > 2 angels
> > > > > > 5 tetras (2 glow light, 3 pristella)
> > > > > > a pleco
> > > > > >
> > > > > > and now I've added the mollies. Will that be too big of a
load?
> It
> > > > > doesn't
> > > > > > seem like it when I write it down but it seems busy in the
tank.
> > > > >
> > > > > I thought a good rule of thumb was one inch of fish per square
inch
> of
> > > > > surface. And I thought angelfish ate tetras?
> > > > >
> > > > > Marcus
> > > > >
> > > > >
> > > >
> > > > One fairly common standard (but not fully accurate) is one inch
of
> fish
> > > per
> > > > gallon of water. That equates to about one inch of fish for
every
> > twenty
> > > > square inches of surface.
> > > > Using a standard 15 gallon tank with a surface of 12" x 24",
that's
> 288
> > > > square inches, or more than twenty feet of fish using your rule.
> > > > Not all angels eat all tetras. A better statement would be
almost all
> > > fish
> > > > will eat fish small enough to fit in their mouth.
> > >
> > > Yes, I was a bit confused when I wrote that. But I find the 1 inch
per
> > > gallon rule innacurate, particularly as a 1 inch fish weighs about
1/8th
> > of
> > > a 2 inch fish of the same shape, so it clearly uses more like 1/8th
of
> the
> > > oxygen and produces a corresponding amount of waste products.
> > >
> > > This table should be a bit more accurate, therefore. (It is not
mine)
> > >
> > > Size No. Per cm2 of surface
> Approx.
> > > cm2 per fish
> > >
> > > 1 400
> > > 2.5
> > > 2 110
> > > 9
> > > 3 50
> > > 20
> > > 4 25
> > > 40
> > > 5 12
> > > 80
> > > 6 8
> > > 125
> > > 8 5
> > > 200
> > > 10 2
> > > 500
> > > 12 1
> > > 750
> > > 15 1
> > > 1100
> > >
> > > HTH
> > >
> > > Marcus
> > >
> > >
> >
> > You are right in that fish mass has more of an impact than fish
length.
> > Unfortunately, while mass is definitely better but harder to
estimate,
> there
> > are also factors such as activity, age, aquarium parameters, and
types of
> > food.
> > Your chart still needs some work. The first column sets out square
cm's
> of
> > fish but it might be better to set out cubic cm's. The second column
sets
> > out square cm's, and how many one inch fish could be stocked in an
> aquarium
> > with a (roughly converted) one inch square surface.
> > You can try but I don't think anyone will deveope anything better
than a
> > rough guide for 'bread and butter' fish from the LFS. Far better to
learn
> > from the experience of others and add that to one's own observations.
> >
> > Jim
>
> The table wrapped. There was supposed to be three columns. The first
column
> was fish length in cm, and the last column ended up under the first
column.
> Here it is again
>
> Size/cm Fish/1000 cm2 surface cm2 / fish
>
> 1 400 2.5
> 2 110 9
> 3 50 20
> 4 25 40
> 5 12 80
> 6 8 125
> 8 5 200
> 10 2 500
> 12 1 750
> 15 1 1100
>
> First column, length of fish in centimeters.
> Second column, number of that size fish you can have in each 1000 cm2
of
> surface area.
> Third column, approximate number of square centimeters of surface
needed for
> each fish of that size.
>
> Marcus

Where did this chart originate from? IMHO, it has a small bit of merit,
but deriving a relationship between body size and a surface area requires
a known rate of circulation (like zero). As soon as you double your
water flow immediately under the surface, your theoretical bio-load
capacity doubles. Triple the flow and you triple your bio-load capacity.
Surface calculations were more popular in the 60s. As filtration systems
became more reliable, powerful and were left on 24 hours a day, deriving
a relationship to water volume became more practical. The surface
calculation is still useful for calculating the mean time to oxygenation
stress in the event of a power failure. You then just have to use a
fudge factor for species. Otos will expire early, before others are
showing stress, and labyrinth equipped fish, and many catfish will labour
along much longer than the others.

I really think the 1"/gal has nothing to do with oxygenation, (or with
anything else tangible). The closest comparison might be biological
capacity. If you have a 20g rated filter on a 20g tank, than having ten
2" fish probably gives you a comfortable operating margin for safety.
You could double the filtration, but now the tank might get too crowded,
depending on the species (some species would be too crowded with ten 2"
in a 20g). No matter how useless these charts and tables are, we still
need them, (if nothing else, to poke holes in their logic ;~)

NetMax

[Marcus Fox]

> > Size/cm Fish/1000 cm2 surface cm2 / fish
> >
> > 1 400 2.5
> > 2 110 9
> > 3 50 20
> > 4 25 40
> > 5 12 80
> > 6 8 125
> > 8 5 200
> > 10 2 500
> > 12 1 750
> > 15 1 1100
> >
> > First column, length of fish in centimeters.
> > Second column, number of that size fish you can have in each 1000 cm2
> of
> > surface area.
> > Third column, approximate number of square centimeters of surface
> needed for
> > each fish of that size.
> >
> > Marcus
>
> Where did this chart originate from?

Dr Axelrod's Mini Atlas of freshwater aquarium fishes, page 715, put forward
by one of the authors, Dr. Cliff W. Emmens.

Marcus

[Graham Broadbridge]

Can you guys please trim your posts.

"Marcus Fox" > wrote in
message ...
>
> "Jim Brown" > wrote in message
> .. .
> >
> > Marcus Fox > wrote in
> message
> > ...
> > >
> > > "Jim Brown" > wrote in message
> > > .. .
> > > >
> > > > Marcus Fox > wrote in
> > > message
> > > > ...
> > > > >
> > > > > "Cplus" > wrote in message
> > > > > e.rogers.com...

[Marcus Fox]

"Graham Broadbridge" <graham at peachy dot org> wrote in message
...
> Can you guys please trim your posts.

I did, lol - but my last post wasn't showing up on my news server, so here
it is again, just in case...

> > Size/cm Fish/1000 cm2 surface cm2 / fish
> >
> > 1 400 2.5
> > 2 110 9
> > 3 50 20
> > 4 25 40
> > 5 12 80
> > 6 8 125
> > 8 5 200
> > 10 2 500
> > 12 1 750
> > 15 1 1100
> >
> > First column, length of fish in centimeters.
> > Second column, number of that size fish you can have in each 1000 cm2
> of
> > surface area.
> > Third column, approximate number of square centimeters of surface
> needed for
> > each fish of that size.
> >
> > Marcus
>
> Where did this chart originate from?

Dr Axelrod's Mini Atlas of freshwater aquarium fishes, page 715, put forward
by one of the authors, Dr. Cliff W. Emmens.

Marcus