Importance of Acclimatisation

After spending alot of time and effort researching the perfect addition to your aquarium and then outlaying your hard earned money on the perfect new inhabitant of your tank your wouldnt want to see it die as soon as it goes in. In different aquariums the levels of the water after diffrent in some cases these diffrences can be rather extreme, diffrences in ph, salinity, temperature, and alot of other parameters. A sudden change in water conditions is enough to kill alot of fish, corals, and other life so it is important to slowly change the condition of the water they are in to the conditions of your tank. This reduces stress and helps your new investment have the best chance of survival.
Methods of Acclimatisation

IT IS VERY IMPORTANT TO NOT RUSH THIS PROCESSES! Doing so might kill your new livestock.

Floating Bag

One of the easyest methods of acclimatising new livestock to your tank is the floating bag method.
this involves 

  1. First turn off the aquarium lights and dim the lighting in the room if possible.
  2. Then float the bag containing your new livestock in its new location (preferably a quarantine tank) for 15 minutes to bring the temperature of the water to the same level of the new location without opening the bag.
  3. After this open the bag either by cutting below the clip or elastic band holding the bag closed then turning the sides of the bag down a bit over an inch to trap some air to the bag still floats.
  4. Then add half a cup of the tanks water to the bag every 5 minutes until the bag is full.
  5. When the bag is full remove the bag from the tank and discard about half the water, it is best to do this over a bucket so not to risk discarding your livestock.
  6. Return the bag to the tank and again add half a cup of tank water every 5 minutes until full.
  7. Using a small net, remove the livestock from the back and place it in its new home. Leaving the lights off for a few hours for it to get used to its new surroundings.
  8. Discard the water in the bag as it is very important not to contaminate your water with the water from another source to reduce the chance of undesirable pests, chemicals from treatments at the supplier or diseases from entering your tank.

This method can be used for a large number of fish and other tank inhabitants, however you should always research your specific item to decide the best method.

The Drip Method.

For more sensitive fish, invertebrates and corals a slower method of acclimation is needed to ensure they suffer the least stress possible. 

  1. With the lights off float the bag containing the livestock in its new tank for 15 minutes to bring the temperature to that of the its new home.
  2. Empty the bag into a small clean bucket (10L or so, obviously if you have a large fish that wont fit then a bigger one will be needed) designated only for aquarium use. 
    • It is important that this be clean as chemicals such as soaps and bleaches will kill your livestock.
    • Be sure not to expose sensitive inverterbates to air.
    • This bucket needs to be below the tank that the livestock is going into, use a seperate bucket for each bag.
  3. Using airline tubing either with a few knots, a few pegs or preferable a plastic regulator valve, start a syphon from your tank into the bucket.
  4. Slow the flow of the syphon to a few drips per second, ether by turning the regulator knob, or by tighting one of the knots in the airline, or adding pegs.
  5. When the water in the bucket doubles or even triples for some more sensitve invertbrates, remove about half of it.
  6. Then when the water again is double or more you can net the livestock and add it to the tank.
  7. For the more sensitive invertebrates that can not be out of the water, scoop them out of the bucket using  a small clean container and add them to the tank by submerging the container underwater then removing the livestock and taking the bag or container out of the tank. the small amount of water transferred shouldn’t harm anything. 
  8. Discard the water in the bucket
  9. Leave the lights off for at least 4 hours to let the new inhabitants settle.

Additional Important Information


  • Be patient – rushing the acclimation procedure can kill your new livestock and will cause more stress.
  • Even if your new inhabitant appears to be dead when you get it home, still try acclimation (using the drip method) as they have been known to come good.
  • Never put air-stone into the bag or bucket when acclimating. This will cause the pH of its water to rise and the ammonia present in the bag from the livestocks waste will become lethal at higher ph levels.
  • To reduce stress on the new arrivals leave the lights off for 4 hours after introducing them to allow them to settle into their new home


  • Some fish need to be netted with a plastic net as a mesh will get caught on their fins, spines ect.
  • Some territorial fish might be aggressive towards the new comer, some ways around this include rearranging the liverock in the tank to confuse the territorial fish so it sets up new territory and the new fish has a chance to find its own.


  • Never touch the “fleshy” part of live coral when handling them, always use the base rock or frag plug they are on.
  • Some corals produce excess slime when they are shipped, after acclimation hold them using the rock or plug they are on and shake the coral lightly in the bag or bucket before placing it into the aquarium, to avoid damage, remember to only hold them using the base rock or plug.
  • Many corals will not open for several days after relocation.
  • Inspect corals for worms, and crabs and snails before adding them to the aqurium as some are harmful and can multiply and wipe out your corals.
  • Coral should be correctly dipped as well before adding to the aquarium.

Other Invertebrates

  • Sponges, clams, scallops, and gorgonias should never be directly exposed to air. Always use the bag they came in or a small clean container to transfer them submerged to prevent damage or death.
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