Fishkeeping - A new tank without cycling

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A new tank without cycling

Jim Morcombe wrote:

atomweaver wrote:
Zëbulon wrote in
:

"nut" wrote in message
...

Zëbulon wrote:

"Tynk" wrote in message
glegroups.com...

You cannot set such a vague "rule" when there are way too many
variables when it comes to stocking a fish...much more than it's
size in inches.

======================
Such as the fact a 1" goldfish passes a lot more waste than a 1"
guppy.

The rule was for tropical fish, not coldwater.

=================
This is true but how many newbies know that? They come here all the
time asking about putting tropicals with goldfish. Some people keep
them together successfully.

Also, some tropicals have a lot more bulk per inch than others.

It would be good to have something a little more accurate than the inch
per gallon guide. In one article I read, they made the excellent
suggestion that the "real" main limiting factors for an aquarium are
mass of fish as adults vs. water surface area of the tank (which is a
more measurable equivalent to oxygen transfer rate), with different
stocking ratios for Fresh, brackish, salt, (and warm and cold) waters.

You could further modify this by multiplier factors considering things
like whether additional oxygenation/waste management is available
(airstone, planted tank etc), or fractional multipliers for if you're
keeping only carnivorous fish (more waste). The main advantage is that
you get a better feel for the differences in body types. The drawback
is that I haven't found many sources which report average/typical adult
fish mass. This is one of them;

http://www.aquariumfish.com/aquarium...aid=323&cid=53
&search

For common freshwater species, that table gives you neons at 0.2g and
7cm discus at 19 g. If anyone knows of other resources which report
more adult typical mass values for FW aquarium species, I'd love to see
it. I could bring my fish into work, and weigh each immersed in a fixed
volume in a graduated cylinder (and then weigh the water afterwards to
calculate their mass), but I'd rather save them the stress of such a
trip.

Even after all that, metabolic rate doesn't scale directly with mass of
the fish, but this would be a step in a more accurate direction.

DaveZ
Atom Weaver

As you said, "water surface area of the tank (which is a
more measurable equivalent to oxygen transfer rate)". Oxygen is one
limiting factor, but this should be determined by the
filtration/oxygenation equipment you have in the tank, not surface area.

Yeah. I don't think surface area is a big factor if you have circulation and
are moving that surface.

Another fish-keeping myth is that "fish grow to the size of the tank".
There is some truth in this, although I haven't figured out the
mechanism yet. Perhaps the water quality determins the size of the fish
and as the fish grow too large for the tank/filtration system.
Consequently there is a higher level of nitrite or some other factor
that slows the growth of the fish.

What happens is that fish grow normally in good conditions and they grow
poorly in poor conditions. Once the various N levels rise, even if its just
very high NO3, then the fish will not grow well. And there are other
toxins, heavy metals, hormones and the rest that will make conditions poor.
So fish will often seem to 'grow to the size of the tank' but what it means
is that the fish are in poor conditions and not healthy.

In any case, if you put in a filtration/oxygenation system four times
the recomended size, you can support more fish and your fish will grow
faster.

Well, for goldfish you need about 4x anyway. The filtration certainly helps.
You keep the toxin levels down, esp NH3 and NO2, and the fish will do
better. You will still need to remove the NO3 and other toxins with plants
and water changes. With a highly overstocked tank you are going to need
water changes very often to keep conditions from becoming poor.

In other words, your recomendations for rules of fish stocking needs to
take into account factors such as water flow rates, filtration
effectiveness and oxygenation.

Yes, I'd agree with that. It pays not to push things too far as maintenance
becomes harder and there is more risk or a sudden catastrophic failure in
the balance.

On the topic of measuring fish, I always have trouble with the method
you mentioned. I find it is easier and more accurate to measure the
length of the fish and the estimate its mass by interpolation. But
then, I'm a bit of a klutz and my students are even worse. (I first
discovered the effect of incorrect filter sizes on growth rates when I
disassembled the tanks we had used for a growth rate experiment that
failed only to find that the students had mixed up the filters and that
the filter sizes explained the strange results).

Stocking is a hard one. It becomes a feel rather than a calculation. Water
parameters and slow stocking is a good way to feel your way into a tank.

A new tank without cycling

Jim Morcombe wrote:
As you said, "water surface area of the tank (which is a
more measurable equivalent to oxygen transfer rate)". Oxygen is one
limiting factor, but this should be determined by the
filtration/oxygenation equipment you have in the tank, not surface area.

I have found a combination of filtration (type of filtration also makes
a difference), circulation, AND surface are make a difference. As an
example, there were these tall narrow in diameter bullet shaped
aquariums that were popular in the early 1980s, many of my clients
purchased them (not from me, I did not sell them). I installed
comparable filters, air pumps, ECT., yet the capacity of these
aquariums were not as high as the more standard rectangular aquariums I
maintained (as measured by ammonia spikes, nitrites, nitrates,
dissolved oxygen and most importantly, general fish health and
longevity.

Another fish-keeping myth is that "fish grow to the size of the tank".
There is some truth in this, although I haven't figured out the
mechanism yet. Perhaps the water quality determins the size of the fish
and as the fish grow too large for the tank/filtration system.
Consequently there is a higher level of nitrite or some other factor
that slows the growth of the fish.

As you stated, I have found many mechanisms here, nitrates (not
nitrites) has an effect on growth of fish. I have not conducted any
serious tests here, but you raise some interesting points. For instance
in the case of goldfish in under sized aquariums (which is all too
common for GF), I have noticed in a few tanks (not many as I have not
purposefully tried to push the over crowding rule), that goldfish will
grow quickly in very healthy, well filtered, excellent water parameter
aquariums vs. clients who have called me out to small aquariums with
poor conditions that are crowded with GF where the customers has argued
that they have had these fish for "years" in the small aquarium, yet
these fish are small. Of coarse the term here is stunting and these
fish rarely thrive and live as long.

In any case, if you put in a filtration/oxygenation system four times
the recomended size, you can support more fish and your fish will grow
faster.

In other words, your recomendations for rules of fish stocking needs to
take into account factors such as water flow rates, filtration
effectiveness and oxygenation.

I agree, you raise many good points, but surface are is still a major
factor. I mention all these factors in my basic FW aquarium article:
http://www.americanaquariumproducts....rinciples.html

Carl

A new tank without cycling

Jim Morcombe wrote in
:

atomweaver wrote:

It would be good to have something a little more accurate than the
inch per gallon guide. In one article I read, they made the
excellent suggestion that the "real" main limiting factors for an
aquarium are mass of fish as adults vs. water surface area of the
tank (which is a more measurable equivalent to oxygen transfer rate),
with different stocking ratios for Fresh, brackish, salt, (and warm
and cold) waters.

You could further modify this by multiplier factors considering
things
like whether additional oxygenation/waste management is available
(airstone, planted tank etc), or fractional multipliers for if you're
keeping only carnivorous fish (more waste). The main advantage is
that you get a better feel for the differences in body types. The
drawback is that I haven't found many sources which report
average/typical adult fish mass. This is one of them;

http://www.aquariumfish.com/aquarium...aid=323&cid=53
&search

For common freshwater species, that table gives you neons at 0.2g and
7cm discus at 19 g. If anyone knows of other resources which report
more adult typical mass values for FW aquarium species, I'd love to
see it. I could bring my fish into work, and weigh each immersed in
a fixed volume in a graduated cylinder (and then weigh the water
afterwards to calculate their mass), but I'd rather save them the
stress of such a trip.

Even after all that, metabolic rate doesn't scale directly with mass
of the fish, but this would be a step in a more accurate direction.

DaveZ
Atom Weaver

As you said, "water surface area of the tank (which is a
more measurable equivalent to oxygen transfer rate)". Oxygen is one
limiting factor, but this should be determined by the
filtration/oxygenation equipment you have in the tank, not surface
area.

Hm. Really? I knew that aggressive oxygenation could increase stocking
levels, but I've never heard the claim before that filtration determines
oxygenation levels (determines, as in, "is the primary/key factor"). I
suppose a turbulent flow or any other filtration method that increases the
air-water interface would alter oxygen transfer, but thats just another way
of raising water surface area... If it really was a big factor, one would
expect that sumps would be more popular in FW setups.
I think if you're trying to develop a "rule of thumb" which is improved
over the "inch per gallon" rule system size has to be taken into account
somehow. Trading filtration/oxygenation capacity for surface area (and
indirectly, tank size) doesn't seem like a wise trade off.

In any case, if you put in a filtration/oxygenation system four times
the recomended size, you can support more fish and your fish will grow
faster.

In other words, your recomendations for rules of fish stocking needs
to take into account factors such as water flow rates, filtration
effectiveness and oxygenation.

Right. Thats what I was getting at, when I wrote:

"You could further modify this by multiplier factors considering things
like whether additional oxygenation/waste management is available
(airstone, planted tank etc), or fractional multipliers for if you're
keeping only carnivorous fish (more waste)."

So, you develop a base stocking guideline which says (and these numbers are
totally arbitrary):

2.5 g of adult fish mass per 10 cm^2 of surface area (assumes a HOB
filter with low turbulence, freshwater, unplanted, 76-78 degF).

Airstone mulitplier is 1.3 (if airstone is properly sized to the tank)
Carnivore/messy eater multiplier is 0.8
Bio wheel multiplier is 1.05
Over feeding multiplier is 0.75
Heavy water change (75%/week) multiplier is 1.2
High temp multiplier is X
Low temp multiplier is Y
etc.

Again, I'm pulling numbers out of thin air, just to demonstrate how the
guideline would work. As I write out the multiplier list, it strikes me
that the more multipliers you apply, the less accurate the guideline would
become.

On the topic of measuring fish, I always have trouble with the method
you mentioned. I find it is easier and more accurate to measure the
length of the fish and the estimate its mass by interpolation. But
then, I'm a bit of a klutz and my students are even worse. (I first
discovered the effect of incorrect filter sizes on growth rates when I
disassembled the tanks we had used for a growth rate experiment that
failed only to find that the students had mixed up the filters and
that the filter sizes explained the strange results).

Yeah, I guess I think of the tools I use at work first, rather than trust
to my capabilities of interpolation. I measure polymer densities by the
Eureka-plus-Scale method, and it struck me as a way to do things with fish,
too. :) Something tells me the fish would be less co-operative than the
plastic. Heh.

Thanks for the reply.

DaveZ
Atom Weaver