How to Acclimate Betta Fish (A Matter of Some Debate)

The best method for how to acclimate fish is a highly debated topic online. No matter what I say in this article, there will be folks who say I’ve got it all wrong and their method is better.

There will be some who will claim I am overly cautious and others will say I am not cautious enough.

I always drip acclimate my fish, but many in the industry prefer the “plop and drop” method. For plop and drop, they float the fish’s bag to get it up to temp and then immediately open the bag into a net, discard the water and drop the fish into the tank.

There are many prominent aquarium experts who state that they get the same survival rate with plop and drop that they do with drip acclimation, but without all the work you have to do for dripping.

I beg to differ with these folks. I have found that I have a significantly higher survival rate with drip acclimation. I would lose 10%-20% of fish with plop and drop versus only about 1% using drip acclimation.

So, I’m in favor of dripping. Today, I will go over how I drip acclimate betta fish and what equipment I use. It’s all cheap, readily available stuff, most of which you probably already own if you’re in the aquarium hobby.

How to Acclimate a Betta Fish

Water Chemistry

You need to be particularly careful if you are acclimating a Betta that has been shipped to you.

Fish put off wastes in the form of urine and feces come from their digestive system and CO2 from their respiration. 

As urine and feces rot in the bag, they put off highly toxic ammonia. 

While the container is sealed up, CO2 and ammonia interact, binding the ammonia (NH3) into a much less toxic substance, ammonium (NH4+).

This is great because it means the ammonia doesn’t poison the fish during shipping. 

But it is also very bad because the ammonia turns back into its super toxic form as soon as you open the container and let the CO2 out!! Within seconds there’s a huge ammonia spike.

Make sure you add a few drops of Prime to the fish’s water as soon as you open the shipping bag!!

Please, be warned, opening a shipping bag without adding Prime, or some other ammonia detoxifier, can result in the death of your fish due to acute ammonia poisoning!! 

Prime will keep the ammonia bound into ammonium without the CO2. If you want to use a different water conditioner, make sure that it detoxifies ammonia and not just chlorine. 

Procedure for Acclimating a Betta Fish

The following steps are meant to safely and gently acclimate fish, even if the parameters in the original container are radically different from those in the aquarium.

Equipment: 

  • 3 gallon (11 liter) bucket
  • Aquarium airline tubing
  • Airline control valve (aka T valve)
  • Scissors 
  • Water conditioner that detoxifies ammonia (Seachem Prime is my first choice)
  • Small clamps to hold airline hose
  • Eye dropper (optional but very helpful)
  • Multipurpose Dip & Pour (optional but super helpful)
Preview Product
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AKOAK 10 Pack Blue Plastic Fish Tank Air Pump Control Valves Aquarium Hose Connector 2 Way Adjustment Control Valves Aquatic Accessories Supplies AKOAK 10 Pack Blue Plastic Fish Tank Air Pump Control Valves Aquarium Hose Connector 2 Way...
Seachem Prime Fresh and Saltwater Conditioner - Chemical Remover and Detoxifier 500 ml Seachem Prime Fresh and Saltwater Conditioner - Chemical Remover and Detoxifier 500 ml
Lee's 18673 Break Resistant Specimen Container, Large Lee's 18673 Break Resistant Specimen Container, Large

Last update on 2023-01-28 / Commissions Earned / Images from Amazon Product Advertising API

Steps: 

  1. You first need to get your fish acclimated to the temperature of your aquarium. How you acclimate your fish for temp is going to be affected by the kind of container they are in:
    1. Regular plastic bag – keep the bag sealed. Float the bag in the aquarium for 20 minutes. You can clamp the bag to the rim of the aquarium if needed. If your fish was shipped to you, be sure to add 2-3 drops of Prime immediately after you cut open the bag. This will neutralize any built up ammonia, nitrate or nitrite that is in the bag water.
    2. Breather bag – do not, under any circumstances, float a breather bag!! It will suffocate your fish. Open the breather bag, and immediately add a few drops of Prime.
      Transfer the fish and all the water into a regular plastic fish bag, or preferably, into a Dip & Pour. Float the bag or hang the Dip & Pour on the inside of the aquarium so that it is partially submerged under the tank water. The temp in the fish water will slowly equalize with the tank over the next 20-30 minutes.
    3. Plastic cup – open the top of the cup and add 2 drops of Prime. You can clamp the cup inside the tank, or transfer the fish and all the water into a regular plastic fish bag, or preferably, into a Dip & Pour.
      Float the bag or hang the Dip & Pour on the inside of the aquarium so that it is partially submerged under the tank water. The temp in the fish water will slowly equalize with the tank over the next 20-30 minutes.
  2. While the temperature equalizes, get your drip kit ready. Run a piece of airline tubing from the aquarium to the bucket. Clamp the end going into the tank in place. Make sure your tubing can easily reach your bucket and cut it to fit.
  3. Cut the airline again a few feet up from the end that goes into the bucket. Install the control valve to splice the two ends back together.
  4. Transfer the fish and the water from the container into the bucket. If you’re using a Dip & Pour, you can just place the whole thing inside the bucket.
  5. Suck on the bucket end of the airline tubing to start a siphon. Turn the knob on the control valve to reduce the water flow to only a few drops per second. If you do not have a control valve, you can knot the tubing several times to restrict the water flow to a slow drip.
  6. Let the tank water drip into the fish’s original water until the water volume is roughly doubled. Then scoop out about half the water, and drip until the water doubles again. Scoop and refill again.
  7. Net the fish and place them in the aquarium.
  8. Top off the aquarium if needed. 

Final Thoughts

Not everyone in the hobby agrees with how to acclimate fish. Some will say that my method is extreme overkill, especially for a Betta, but I like to be overly cautious when it comes to fish health. 

Sudden parameter changes can highly stress fish, making them susceptible to opportunistic pathogens. 

Better to be safe than sorry and I’ve had good results with these steps.

I hope you find this article helpful.

I wish you and your fish the very best!

Katherine Morgan
Katherine Morgan

Hey, there! I'm Katherine from Northwest Florida. A nunchuck specialist, I've kept aquariums for over two decades, enjoy experimenting with low-tech planted setups and an avid South American cichlid enthusiast. If You'd like to see more of my tanks, check out my Instagram

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