this was written with bichirs in mind but applies to all fish really
STRESS
Stress in a broad context,is any reaction to factors that drive physiological systems outside the normal range.Stess can affect fish endocrine systems and result in supression of the immune system,thereby decreasing a fishes abilty to fight infections,disease and parasites that normaly might not present of a physiological challenge.
There are two different kinds of stress that concerns us"acute"stress or short term stress and "chronic"or long term stress.Acute or short term stress may last only a few hours or a few days this often results in increased levels of catecholamines(epinephrine,norepinephrine)and cortisol.Increased levels of these hormones in respose to the stressor.These changes can result osmotic imbalances,decrease in white blood cell counts and a dimminished response to infectious agents.
Causes of short term stress includes but are not limited to the below.
Netting,moving and transporting
improper aclimation to new tank
chemical substances (medication)bichirs do not tolerate some medications primaraly copper based meds
tho current thought is many older copper based meds contained a fair amount of zinc
fight or flight response
Indications of "acute" or short term stress include the following
Faded coloration(this is more noticable on sensgals and lapradei)
Lack of appetite
hiding
rapid gill movement
excess slimecoat
to help reduce"acute"stress to a minimum try the following
when you bring a new bichir home place it in its qt preferably in a darkened area
and simply leave it alone for 24 hours.so it can begin settleing in.
Properly aclimate your new fish this involes more than floating the bag in the tank
which only equlizes the tempurature.
Netting and moving do this only when needed ie. moving them to bigger tanks or removing them
to a hospital tank for treatment.
Long term or chronic stress
In the wild fish can move to more desirable conditions and avoid stressful situations
however in captivity fish are often subjected to relatively long periods of stress.A common
cause of death in stressed captive fish is osmotic inbalance.A fish exposed to chronic stress
has 2 options adapt or eventualy die.even if a fish adapts growth rate and general health will
be reduced during the period of adoptation.The systems responsible for the basic
metabolic functions such as the nervous system,the respiratory system and the systems that
control osmoregulation have a higher priority than growth or reproduction.Under conditions
of little or no stress there is an energy surplus that can be put towards growth and reproduction.
Chronic stress has also been shown to cause changes at the celluar and tissue levels especially
the liver,gills and spleen to the point of failure.
causes of chronic stress include but are not limited to
rapid temperture changes
rapid changes in water chemistry (pH)
overly agressive tankmates
poor water qualtiy
Prevention
Rapid tempurture fluctuations:Can be avoided by buying a quality heater
if the heater is placed exposed in the tank either buy or make a heater
guard this will prevent heater burns.
Rapid changes in water chemistry
pH) do not atempt to adjust your source water pH
let your fish adjust to the natural pH of your source water.
Poor water conditions:Maintian a proper waterchange scheudule.
Water quality maintain a schedule to change the water and clean the tank this prevents
build up of waste and other substances.
Overcrowding
o not overcrowd your tank when purchasing fish think of the adult sizes not how big they
when you buy them usually as juveniles.
Poor diet
ffer a variety of foods not just one thing and if using feeders either quarantine
them or better yet raise your own.
Agressive tankmates:Bichirs are generally non agressive tankmates.If you observe constant bullying
seperate the bully
