Pond Livestock Acclimation

by Robert Fenner
Reprinted with permission, from Bob's website in San Diego:  www.wetwebmedia.com
Aquarticles

  Surprising to many non-a"fish"ionados, many organisms are lost due to inadequate, improper introduction. Collectors, distributors, transshippers, wholesalers, retailers and hobbyists actually suffer most losses when receiving new livestock. 
  When placing fishes into a new environment there arises the possibility of physical, chemical, biological and social shock.
  This article identifies and shows how to reduce these stresses, and how to ameliorate the effects of stress after it has occurred.
  There are a myriad of acclimation techniques; depending on the livestock' genetic and developmental history and conditions at shipping; these are all to some degree appropriate and successful. Many losses can be avoided or reduced with the information provided here.

An Overview of Fish Stressors:

Physical Stressors:
  To many fishes, even a small change in temperature over a short time is detrimental; thus attempts are made to equilibrate the temperatures in the new and old environs. Often this is done by floating the plastic shipping bags the fishes are transported in, in the pond. This process should continue for 20-30 or more minutes, depending on the amount of water shipped, the temperature difference, and the apparent strain the livestock is undergoing. It's often a good idea to monitor the temperature in both environments.
  Leave the bag(s) sealed. Opening the floating bag is a poor idea as the concentration gradient of oxygen may be higher if left closed and an open bag usually reduces surface area, and therefore gas exchange. Keep this in mind and maintain some surface area in the bag and/or add a mechanical aerator (an airstone) while adjusting for temperature.
  It is also important that the bags be shielded from direct sunlight during this time; especially on a hot day, as this will heat the water in the bags too much, too soon. The effects of elevated temperature are synergistically bad; decreasing gas solubility in the bag, increasing metabolic rate, frightening the fish; in general cooking them.
  Be aware that thermally-shocked fishes may appear and behave "normal" on arrival and placement; only to die mysteriously within a few days. The biochemical and physical damage resulting  from thermal shock often catches up later. This is an all too often occurrence in transferring livestock too late into a cold season into warmer quarters.
  There is a school of thought that discounts the advantages of mediating temperature affects and admittedly if there is a time constraint and if the new fishes are under a lost of stress, they are often better off being introduced immediately. This is much more preferable if the water they are being moved into is warmer than the transported water. In general, cold water shock causes a great deal more harm than warm water shock.
  Finally, regarding an "old-wives tale" about the detrimental effects of floating polyethylene bags. In the latter 1960's there circulated a myth that this practice (THE AQUARIUM, magazine, June 1968, Vol. 1 no. 8 series II, or George Demmer, To float of not to float, FAMA 7/95.) would kill fish. This is hogwash.

Chemical Stressors:
  To some extent, water will vary chemically from source to source. Sometimes the successful introduction of new fish into a pond will largely depend on the chemical composition of the water involved.
  It's often a good idea to try reducing some of the chemical shock by mixing water from your system with the shipping water on arrival or after floating. Do not put the shipping water into your established system! Especially with "wild-caught" specimens, the risk of introduction of chemical pollutants and undesirable organisms is not worth it. However, there are two scenarios in which adding shipping water may be beneficial: 1) When the receiving set-up is brand new and has not been properly "seeded" with bacteria and 2) When "wild" stock chemical conditions are so different that even biologically polluted shipping water is better mixed in than all new "clean".
  There are numerous techniques ranging from ingenious drip systems to simply adding a portion of new water to the shipping bag a few times every few minutes, to floating traps to... The most appropriate and successful method I've found is detailed below.

Biological Stressors:
There are three major components to livestock health:
A) It's initial condition, B) The suitability of it's environment and C) The presence and virulence of infectious organisms.
A) When you acquire fishes, make sure they are in good health. Buy from reputable sources. If you can, make a thorough inspection of their facilities. Are the fish being well fed? Are the plants well maintained? Is the staff knowledgeable and interested?
B) Too many people's ponds are ecological messes. Always check for the requirements and compatibility of the organisms in your care. You determine their world. What conditions have they been raised and kept in recently? This may be vastly different if you're dealing with cultured versus wild stocks. When possible, deal with a "local" source.
C) For most people it's hard to determine when you're adding undesirable micro-organisms. Keep your sights set on providing an optimized environment and follow the suggested acclimation process to avoid trouble. Never add to a system in which there is already a problem.

Social Stressors:
It's often important which order the fishes are introduced, in what number, of what size, sex and type. Sometimes, if the fishes grow up together, they get along well even though in a natural environment one would prey upon the other. Always allow for some individual variation in temperament.

A/The Best Method of Acclimation:
  After and while adjusting for temperature differences by floating or slowly adding water from the system to the shipping water, you net out or pour the mixed water through a soft net, and dip the fish in a prepared bath. This dip bath is prepared from water from the system in a bucket with an ounce of 37% food grade formaldehyde per five gallons of dip; and the net with the fishes in it lowered into the bath.
  Depending on the type of species (short dips for scale-less fishes) and size and condition (less for smaller and weaker), this ranges from a few moments to a few minutes as long as the fish is not exhibiting discomfort. Fishes thus acclimated and "dipped" are placed via net into their tank.
  This and other dip/bath solution preparations are sold at pet-fish stores and mail-order. The mixed material should be poured to waste to the sanitary sewer.

The Ideal Set-Up: Quarantine
  Though few "ponderers" will endure the expense, time and trouble, setting up and maintaining a "temporary" "other" pond for waylaying all new introductions (plant and animal) is The only real route to optimizing livestock health. This container can be as simple as a covered kiddie pool.
  By placing newcomers apart from your established system for a couple of weeks, the vast majority of parasites, infectious agents and unwanted "hitchhikers" are eliminated. Further, you are afforded the greatest opportunity for observing the new stock up close.
  Anybody who has been in the hobby, and everybody who has been in the business of aquatic gardening will re-inforce what I'm writing here. You too, will have a "back-up", "breeding/rearing", isolation/quarantine set-up; do it now for properly acclimating livestock.

Conclusion:
  Admittedly, if the fishes are in good shape and the new environment not too unsuitable, you could throw them into their new homes with little ill effect. With attention to proper acclimatization, you will minimize your losses. Remember, hold off feeding for 24 hours after the arrival of your new livestock. Always condition your fish before moving them again. Pay attention to these details and you will be rewarded with happy, healthy new additions to your aquatic garden.