tank capacities

[lgb]

Since I'm going to be setting up another tank (29gal) later this year,
I've been doing what I always do before starting a project, reading
everything I can get my hands on.

I've always heard that tank capacities for freshwater tropicals could be
estimated as 1" of fish for 1 gallon of water. But in my reading, I
came across three different authors who used surface area instead.

This made more sense to me. There's a big difference between 50 gallons
of water in a tall tower and 50 gallons in a long low tank. Of course,
none of the three authors agree on what the ratio shoud be. One says,
10 square inches per inch of fish, one says 12, and the third breaks it
out as follows:

1"-2" fish: 12.5 sq in per fish
2"-3" fish: 17 sq in per fish
3"-4" fish: 20 sq in per fish

Note that these figures vary from 6.25 sq in per in to 5 sq in per in.

And the same author (John Dawes) then sugests 50% overstocking for
cichlids.

So in my 29 gallon tank (12"x30"), I have 360 sq inches. So if I stock
it with 3" fish I can keep 12, 10, or 21 fish, 30 if they're cichlids.

That solves all my problems. I'm glad all the "experts" agree :-).

Note that the middle estimate is almost the same as I'd get with 1" per
gallon. But in a 10 gallon tank 12 sq in would allow 16" of fish, while
for a 75 or 90 gallon tank the number would be identical, 72" of fish.

Any comments?

BTW, once I get this figured out I'll start asking for opinions on the
fish I decide on. I'm sure glad this group exists :-).

--
BNSF = Build Now, Seep Forever

[George Pontis]

In article >,
says...
> Since I'm going to be setting up another tank (29gal) later this year,
> I've been doing what I always do before starting a project, reading
> everything I can get my hands on.
>
> I've always heard that tank capacities for freshwater tropicals could be
> estimated as 1" of fish for 1 gallon of water. But in my reading, I
> came across three different authors who used surface area instead.
>
> This made more sense to me. There's a big difference between 50 gallons
> of water in a tall tower and 50 gallons in a long low tank. Of course,
> none of the three authors agree on what the ratio shoud be. One says,
> 10 square inches per inch of fish, one says 12, and the third breaks it
> out as follows:
>
> 1"-2" fish: 12.5 sq in per fish
> 2"-3" fish: 17 sq in per fish
> 3"-4" fish: 20 sq in per fish
>
> Note that these figures vary from 6.25 sq in per in to 5 sq in per in.
>
> And the same author (John Dawes) then sugests 50% overstocking for
> cichlids.
>
> So in my 29 gallon tank (12"x30"), I have 360 sq inches. So if I stock
> it with 3" fish I can keep 12, 10, or 21 fish, 30 if they're cichlids.
>
> That solves all my problems. I'm glad all the "experts" agree :-).
>
> Note that the middle estimate is almost the same as I'd get with 1" per
> gallon. But in a 10 gallon tank 12 sq in would allow 16" of fish, while
> for a 75 or 90 gallon tank the number would be identical, 72" of fish.
>
> Any comments?

All the numbers seem on the high side for conservative practice. Thirty 3"
cichlids would be excessive by any standards. I believe that your selection would
need to take into account the mass of the fish and their eating habits as much as
just their length. For example, some would question even two 4" oscars in the 29
gallon tank. These popular fish spew food out through their gills as they devour
their hefty meals, generating even more waste than one might expect. And then they
grow larger. Two large goldfish might also be at or over the limit!

Maybe a better way to come up with some numbers is to read up on some fish that
you would like to keep, and then see what recommendations there are for tank sizes
for that particular species. It will be up to you to figure out how to work the
numbers that would apply to combinations. The logic for basing your stocking level
on surface area makes a lot of sense because it relates to oxygen exchange with
the air. If you have a lot of bubbles or water currents rippling the surface then
your environment would be more conducive to heavier stocking (as long as the power
is not interrupted). Maybe in some cases you would choose two or more smaller
species that hang out at different levels in the tank; then the extra height
provides a meaningful benefit.

[Dick]

On Thu, 14 Jul 2005 20:50:06 -0700, lgb > wrote:

>Since I'm going to be setting up another tank (29gal) later this year,
>I've been doing what I always do before starting a project, reading
>everything I can get my hands on.
>
>I've always heard that tank capacities for freshwater tropicals could be
>estimated as 1" of fish for 1 gallon of water. But in my reading, I
>came across three different authors who used surface area instead.
>
>This made more sense to me. There's a big difference between 50 gallons
>of water in a tall tower and 50 gallons in a long low tank. Of course,
>none of the three authors agree on what the ratio shoud be. One says,
>10 square inches per inch of fish, one says 12, and the third breaks it
>out as follows:
>
>1"-2" fish: 12.5 sq in per fish
>2"-3" fish: 17 sq in per fish
>3"-4" fish: 20 sq in per fish
>
>Note that these figures vary from 6.25 sq in per in to 5 sq in per in.
>
>And the same author (John Dawes) then sugests 50% overstocking for
>cichlids.
>
>So in my 29 gallon tank (12"x30"), I have 360 sq inches. So if I stock
>it with 3" fish I can keep 12, 10, or 21 fish, 30 if they're cichlids.
>
>That solves all my problems. I'm glad all the "experts" agree :-).
>
>Note that the middle estimate is almost the same as I'd get with 1" per
>gallon. But in a 10 gallon tank 12 sq in would allow 16" of fish, while
>for a 75 or 90 gallon tank the number would be identical, 72" of fish.
>
>Any comments?
>
>BTW, once I get this figured out I'll start asking for opinions on the
>fish I decide on. I'm sure glad this group exists :-).

I think the question of how many fish is hard to answer. Too many
variables. I have worried about my 75 gallon tank. So many of my
fish have grown over the last 2 years. The tank bottom is 75% covered
with low light plants.

Earlier this year there was a thread discussing electrical outages
and someone suggested running a test to see how long a tank could go
without electricity. I decided to remove the bubbler as a test. I
watched very closely the first hour, checked again first thing after
waking and finally decided my tank was not over populated.

I know I am well over the 1 inch per gallon measure, but my fish spend
much of their time swimming in the bottom half of the tank, so I am no
longer worried about lack of oxygen.

Feeding time is a riot of different fish with smaller fish darting in
with the larger fish. I don't plan to replace fish as they die off,
but I don't worry about over crowding any more.

dick

[Gill Passman]

"Dick" > wrote in message
...
> On Thu, 14 Jul 2005 20:50:06 -0700, lgb > wrote:
>
> >Since I'm going to be setting up another tank (29gal) later this year,
> >I've been doing what I always do before starting a project, reading
> >everything I can get my hands on.
> >
> >I've always heard that tank capacities for freshwater tropicals could be
> >estimated as 1" of fish for 1 gallon of water. But in my reading, I
> >came across three different authors who used surface area instead.
> >
> >This made more sense to me. There's a big difference between 50 gallons
> >of water in a tall tower and 50 gallons in a long low tank. Of course,
> >none of the three authors agree on what the ratio shoud be. One says,
> >10 square inches per inch of fish, one says 12, and the third breaks it
> >out as follows:
> >
> >1"-2" fish: 12.5 sq in per fish
> >2"-3" fish: 17 sq in per fish
> >3"-4" fish: 20 sq in per fish
> >
> >Note that these figures vary from 6.25 sq in per in to 5 sq in per in.
> >
> >And the same author (John Dawes) then sugests 50% overstocking for
> >cichlids.
> >
> >So in my 29 gallon tank (12"x30"), I have 360 sq inches. So if I stock
> >it with 3" fish I can keep 12, 10, or 21 fish, 30 if they're cichlids.
> >
> >That solves all my problems. I'm glad all the "experts" agree :-).
> >
> >Note that the middle estimate is almost the same as I'd get with 1" per
> >gallon. But in a 10 gallon tank 12 sq in would allow 16" of fish, while
> >for a 75 or 90 gallon tank the number would be identical, 72" of fish.
> >
> >Any comments?
> >
> >BTW, once I get this figured out I'll start asking for opinions on the
> >fish I decide on. I'm sure glad this group exists :-).
>
> I think the question of how many fish is hard to answer. Too many
> variables. I have worried about my 75 gallon tank. So many of my
> fish have grown over the last 2 years. The tank bottom is 75% covered
> with low light plants.
>
> Earlier this year there was a thread discussing electrical outages
> and someone suggested running a test to see how long a tank could go
> without electricity. I decided to remove the bubbler as a test. I
> watched very closely the first hour, checked again first thing after
> waking and finally decided my tank was not over populated.
>
> I know I am well over the 1 inch per gallon measure, but my fish spend
> much of their time swimming in the bottom half of the tank, so I am no
> longer worried about lack of oxygen.
>
> Feeding time is a riot of different fish with smaller fish darting in
> with the larger fish. I don't plan to replace fish as they die off,
> but I don't worry about over crowding any more.
>
> dick

I think the important thing to take on board is that going over these
arbitary limits when stocking a tank means increased maintenance and water
changes. I am almost certainly over the "1 inch" limit in two of the tanks
but not greatly - so these are the ones that get better filtration and more
maintenance. Another factor is how the space is used - by this I mean
bottom, middle and top. If all the fish in the tank tend to be at the top
then this will look and feel more overcrowded.

In one tank, I only replace fish if I see something that I really, really
want and then only if I can't find space elsewhere - the other tank (the
Mbuna tank) I don't plan on replacing any that I have lost because of the
potential for more territorial fights - however they are doing a very good
job in replacing themselves - quite fascinating to watch as the fry slowly
gain in confidence and take on minature Mbuna characteristics.

Gill

[NetMax]

"lgb" > wrote in message
...
> Since I'm going to be setting up another tank (29gal) later this year,
> I've been doing what I always do before starting a project, reading
> everything I can get my hands on.
>
> I've always heard that tank capacities for freshwater tropicals could
> be
> estimated as 1" of fish for 1 gallon of water. But in my reading, I
> came across three different authors who used surface area instead.
>
> This made more sense to me. There's a big difference between 50
> gallons
> of water in a tall tower and 50 gallons in a long low tank. Of course,
> none of the three authors agree on what the ratio shoud be. One says,
> 10 square inches per inch of fish, one says 12, and the third breaks it
> out as follows:
>
> 1"-2" fish: 12.5 sq in per fish
> 2"-3" fish: 17 sq in per fish
> 3"-4" fish: 20 sq in per fish
>
> Note that these figures vary from 6.25 sq in per in to 5 sq in per in.
>
> And the same author (John Dawes) then sugests 50% overstocking for
> cichlids.
>
> So in my 29 gallon tank (12"x30"), I have 360 sq inches. So if I stock
> it with 3" fish I can keep 12, 10, or 21 fish, 30 if they're cichlids.
>
> That solves all my problems. I'm glad all the "experts" agree :-).
>
> Note that the middle estimate is almost the same as I'd get with 1" per
> gallon. But in a 10 gallon tank 12 sq in would allow 16" of fish,
> while
> for a 75 or 90 gallon tank the number would be identical, 72" of fish.
>
> Any comments?
>
> BTW, once I get this figured out I'll start asking for opinions on the
> fish I decide on. I'm sure glad this group exists :-).
>
> --
> BNSF = Build Now, Seep Forever

A discussion on the various methods, for your reading pleasure ;~)
http://www.2cah.com/netmax/basics/stocking/stocking.shtml
--
www.NetMax.tk

[lgb]

In article >,
says...
>
> A discussion on the various methods, for your reading pleasure ;~)
> http://www.2cah.com/netmax/basics/stocking/stocking.shtml
>

Thanks. I just loaded it, but haven't read it yet other than the topic
headings. Looks like you've got it pretty well covered.

Now if you just know where I can find Macropodus ocellatus (Chinese
Paradise Fish) at a price a retiree can afford ... :-).

--
BNSF = Build Now, Seep Forever

[lgb]

In article >,
says...
> > A discussion on the various methods, for your reading pleasure ;~)
> > http://www.2cah.com/netmax/basics/stocking/stocking.shtml
> >
>
> Thanks. I just loaded it, but haven't read it yet other than the topic
> headings. Looks like you've got it pretty well covered.
>
OK, now I've read it - you really do have it covered, and a lot of other
stuff as well. Great website.

--
BNSF = Build Now, Seep Forever