Due to technical difficulties there were several missing portions
of the information Russ was trying to present. Below is the text
of his notes in full:
Good evening. Many of you know that my involvement in aqauriology
has been both as a hobbyists and in the wholesale and retail end
of the pet (fish) business. For tonight's topic, I chose to use
the phrase 'non growth' rather than 'stunting'. I would like to
reserve the word stunt(ing) for future reference in the presentation
because I hate polictical correctness. Not thats there is anything
wrong with it...lol
There will most likely be some questions after the presentation,
but before getting started, I would like employ a disclaimer. Plese
try to not ask a question about, "I have a three year old XYZ
fish that is supposed to grow to 10 inches." "It is now
only 5 inches." "If I place it in a 100 gal tank next
week, will it then grow to it's capable size?" Well, I'll be
straight forward on something like that. I don't know! Nobody will
know. However, the information presented here will hopefully help
determine the odds of it doing so or not doing so.
I should inject at this point that for discussion purposes here,
tonight, I'd like to stick with freshwater, tropicals and what is
generally known as 'ornamental' fish. And, to include common brackish,
without getting into marine husbantry and care of marine fishes.
Although there are same basic similarities as far as growth factors,
lets keep this simple.
Tonight you will have to put this information into perspective.
Unless you are more than just a hobby breeder, and have several
rows of aquariums in a 'fish room', your perspective should be as
a hobbyist.
As a hobbysits, you will strive to acheive a small piece of an
ecological system with selected fish species and plant species,
while maintaining an appropriate environment for the tank inhabitants
to live and thrive. I'm not discounting those who do have several
rows of tanks, but are not 'hobby breeders'. Theres that political
correctness that just bit me.
Lets start by attempting to define what 'stunting' is. In it's
most simple terms, stunting is merely a 'check' in developement.
As far as our fish is concerned,, this can mean either a temporary
or permanently stoppage in developement, or growth. Before delving
into some of the 'root causes', it should be known that a 'stunted'
fish is not the same as a fish that fails to regrow certain portions
of it's body. Failure to regrow an eye or a complete major appendage,
would not constitute stunting anymore than our inability to regrow
a lost finger.
Most of the research I have explored and experienced all point
to ideal "requisites" and "energy allocation"
in determining whether a fish is stunted or is capable of regrowth.
Functional requisites and resulting energy allocation is controlled
by the fish's physiology.
Not withstanding vital organs that may have been damaged through
disease, combat, or congenital defects, physical operations of organs
is regulated in accordance with vital importance to sustaining life.
There are also environmental factors that contribute to the 'ideal'
climate that a fish requires to not only function, but to grow and
reproduce. Keep in mind that fish have developed in regions throughout
the world for millions of years. They have adapted, thrived, and
reproduced in these regions because they are in a favorable situation
that contributes to sustaining the fish's requisits. And they have
evolved in those regions.
Also,(this is important to remember) please keep this point in
mind during this discussion as it relates to growth and reproduction:
"The systems responsible for the basic metabolic functions
necessary for life, such as the nervous system, the respiratory
system, and the systems that control osmoregulation, have a higher
priority for energy than growth or reproduction."
At this time, I like to divide further discussion into two main
categories that would affect growth and nongrowth of our fishes.
ENVIRONMENTAL and PHYSIOLOGICAL
Above, I mentioned requisites and energy allocation in determining
whether a fish is stunted or capable of regrowth. While 'requisites'
encompass both environmental and physilogical factors, energy allocation
and functional requisites of the fish would fall into the physiological
category when we are dealing with our individual aquariums.
99.9% of the environmental factors are controlled by the hobbyist
and can be further broken down into other groupings that could include:
RESOURCE LIMITATION FACTORS and ECOLOGICAL FACTORS
To provide your fish with an ideal requisite that it can live and
thrive (grow and reproduce), the hobbyist must provide an conducive
environment in order for the fish to be physiologically sound. Most
of us have heard the saying that one should purchase the largest
tank they can afford? Actually, one should purchase the largest
tank they can afford to maintain. This is a 'resource limitation'
This is also basically controlled by the hobbyist.
Tank size, stand to support the tank, canopy and light, heater,
thermometer, test kits, water and electric bills, purchasing budget,
and last, but certainly, not least, commitment time towords the
fish's diet and the tank's maintenance. These are resource limitations
factors that must be considered. Providing the type of water that
goes into the aquarium, the type of structure (plants, gravel, and
rocks) that go into the tank, and how they are arranged, actual
fish selection, diet, and how much or how often the fish are feed,
are all ecological factors that should be considered.
At this point you are probably wondering how all this ties into
growth or non-growth. Take a breath. We're getting to it.
Environmental issues such as the amount of toxins, dissolved organic
compounds, total dissolved solids, biological oxygen demand, temperature,
and photo periods can impact the general health and well being of
our fish. Environmental such as resource limitations and ecological
factors play a signifficant role in the fish's physical health and
impact on it's basic physiology. Providing favoralbe resources and
employing sound ecological principles will lead to the relief of
the main cause of non-growth and stunting of a fish. This is 'stress'
Stress, in itself, like stuning, is an effect, and not the root
cause. These root causes have already been identified above. That
is that environmental and physiological factors can lead to stress,
which in-turn can/will lead to non-growth and stunting. So, how
is stress defined? For simplicity sake, lets say it is the physiological
response from the fish to adapt to a stimulus.
These responses to stress situations are part of a series of physiological
reactions called "the general adaptation syndrome" or
adaptive factors. This sydrome is divided into three phases: (1)
the alarm reaction, when hormones are released (2) a stage of resistance,
during which adaptation occurs (3) and, if the fish cannot adapt,
a stage of exhaustion, which can be followed by death.
ACUTE and CHRONIC Stress:
The initial response to an acute stress is called the "fight
or flight" response. As an example, when a fish is pursued
by a predator or fish net, the stress response results in a instantaneous
increase in available energy, which may allow the fish to escape
the predator or elude the fish net. Other energy-requiring functions
such as osmoregulation are temporarly shut down so as much energy
as possible can be focused on escape and evasion. This is a short-term
measure to produce large amounts of energy to deal with an emergency
situation.
Most acute stresses are short-term.
So, the fish either escapes (or deals with the emergency) and the
stress is releived or the fish gets caught or can't deal with the
emergency. In the wild, there is plenty of room to escape both predators
and unfavorable water conditions. In captivity, fish are often subjected
to long perriods of stress from many different causes. A very common
cause of death in captivity as a result of being constantly stressed
is osmotic shock. Remember, a fish cannot correct the osmotic problems
caused by acute (short-term) stress.
Stress also supresses aspects of the immune response. A frequent
results is the outbreak of disease after fish have been subjected
to unfavorable physiological conditions.
A fish exposed to chronic stress can eith adapt to the stress,
or fail to compensate and die. Even if a fish does compensate, its
performance capacity will be reduced during the period of compensation.
Many cases, even after. For example, fish can adapt to rather wide
ranges of temperatures, but within this broard temperature range
there is a preferred range in which the fish will grow and perform
best. The further from this range, the poorer the fish's performance.
Under conditions of little or no stress, there is an energy surplus
that can be put into growth and reproduction. However, the further
conditons are from the preferred range or "requisite",
the greater amounts of energy the fish must use to make the proper
physiological adjustments. A prime example of chronic stress is
poor water quality. If the water quality and other factors causing
the problem are corrected, growth generally improves, and the fish
may begin to reproduce.
There is a lot that can be said about the diet and feeding of fish
that will also impact greatly in determining growth. I've opted
for a general overview rather than typing complex formulas and/or
equations.
Foods loaded with vitamins cannot be overly stressed. Vitamins
are organic compounds that serve as catalysts for many biochemical
reatons in body tissues. *** Deficiency of almost any vitamin can
result in retarded growth and increase susceptability to disease.
So, can a fish that has been kept in a smaller than recomended
tank for an extended period of time, be latter transferred to or
into a favorable environment, and the fish's requisites are met,
resume growth? Yes, it is very possibe, as long as vital organs
are not damaged from the result of disease or chronic stress.
My simple take has been this all along.........keep fishes from
the same regions and continent in water that you can most easily
provide for, feed a balanced diet, and maintain 'requiste' water
permameters. Your fish should grow to it's capacity.
References in books listing a certain pH or temperature, hardness,
etc., was not published for the heck of it. Most very good authors
of those books and references did a great amount of research over
the years to determine most of the known fish requisites. It would
not be unwise to follow their advice once in a while. There are
also a great many folks on this site with enough skills and experience
to help other folks with info on their fish's requisites for growth
and reproduction.
Thank you.
