Acclimating Saltwater Aquarium Fish With the Drip Line Method

Cleaner Shrimp

prilfish / Flickr / CC BY 2.0

One of the leading causes of stress and even death for newly acquired saltwater (and freshwater) fish and invertebrates is shock caused by abrupt changes in their environment, specifically salinity levels, pH, and temperature. If a little time and effort is invested to properly acclimate the new arrivals to their new environment, undue stress and fatalities can be avoided.


Abrupt and extreme changes in salinity, water temperature, pH or other water chemistry parameters cause stress that can literally shock the fish or invertebrate to death. If all these factors are drastically changed at the same time it can lead to a potential disaster.

The Pros

  • The drip line or trickle acclimating method is a safe and gentle way to introduce saltwater fish into a new home and is a fairly simple one to perform.
  • Once the drip line is started and the flow rate is set, it pretty much takes care of itself.
  • This procedure can be used to acclimate all types of marine as well as freshwater fish and invertebrates.
  • Once you have your drip line equipment set up, the next time you need to acclimate new fish or invertebrates you will be able to set it up in about a minute.
  • Commercial drip acclimation kits are available to purchase, making it easy to get all the parts needed.
  • Livestock that needs a long acclimation period, such as marine shrimp (which are very susceptible to pH shock) can easily be acclimated over a longer time, even overnight.

The Cons

  • This method can take some time to complete, often up to two hours, depending on the size of the acclimation container being used.
  • Setting up a drip line is a little more involved than with other acclimation methods.
  • If you are acclimating more than one fish, this means you have to either use a separate acclimation container for each one or put them all together. If you combine the fish, they may fight and injure each other even before you can get them into your aquarium, especially if they are of the same or similar species.
  • It is possible to move too fast and not allow adequate time for proper acclimation.

Acclimation Instructions

  1. Put the fish with enough of the bag water in a bucket or container of sufficient size for the fish to be reasonably covered with the water.
  2. Place an air stone in the bucket or container and supply it with air from an air pump.
  3. Set the bucket on the floor next to the aquarium you will be placing the fish into when done.
  4. Test the water temperature, pH, salinity and ammonia in the bucket. If it varies greatly from the aquarium water, a longer drip acclimation will be needed.
  5. Using some plastic air line tubing and an air valve, set up and run a siphon drip line to the bucket from the aquarium into which you will be placing the fish.
  6. Start the siphon and slowly allow the aquarium water to drip into the bucket, using the air valve to adjust the drip-rate. A normal drip rate is 2-4 drops per second. This will add 12-24 ounces (1 1/2 to 3 cups) of water per hour.
  7. When the water dripped into the bucket equals about two times the original volume of the bag water, test the pH, salinity, and temperature of the bucket water to see if these parameters match that of your aquarium water. If not, keep the drip acclimation going. When they match, acclimation is complete.
  8. Gently remove the fish and place it into the source aquarium of the drip water. Do not add any of the water from the bucket into your aquarium.
  9. Add new water into the aquarium to replace the water dripped into the acclimation bucket (this actually provides a beneficial partial water change to your aquarium).
  10. It is recommended when adding new fish into an established aquarium to add some fish food and then dim the lights. Lower lighting helps reduce stress on the new fish as it settles into the aquarium, and adding the food keeps the other fish busy so they don't bother the new fish.


  • It is helpful to add an ammonia binder such as AmQuel to the bag water in the bucket with the fish in it prior to starting the procedure, as ammonia buildup may still occur while the fish is kept here no matter how long completion of acclimation takes.
  • You don't want to set the water drip-in rate too fast, nor too slow. In most situations, one to two drops per second for slow acclimation and two to four drops per second for quicker acclimation will be about right.
  • If you are acclimating several fishes ​at one time and any are of a toxin-releasing or poisonous stinging nature (e.g. volitans lionfish), it is best to acclimate such species individually in a container of their own.
  • It is always best to put new fish into a quarantine tank for a few weeks, if possible, rather than putting them directly into your main aquarium.
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  2. Hung, Chin-Chang et al. Impacts of pH on the Fitness and Immune System of Pacific White Shrimp. Frontiers in Marine Science, vol. 8, no. 748837, 2021. doi:10.3389/fmars.2021.748837

  3. Oldfield Ronald G. Aggression and welfare in a common aquarium fish, the Midas cichlid. J Appl Anim Welf Sci., vol. 14, no. 4, pp. 340-60, 2011. doi:10.1080/10888705.2011.600664