How to Change Betta Fish Water |How Often to Change Betta Fish Water

Learning how often to change the water in your betta tank, and how to change it is the most important factor in the long term health of your fish. High ammonia and nitrate levels caused by waste aren’t visible but can seriously stress out and cause harm to you bettta.

This article will explain exactly how often to change your betta fish water, as well as in very clear steps exactly how to change your water without harming your betta fish. A video is also included to demonstrate the cleaning process.

How Often To Change your Betta Fish Water

It depends……..yes – not the answer you were looking for. All of the factors below contribute to how frequently your water needs to be changed:

  • What is the size of the tank
  • Is it a filtered tank
  • Is the Betta Fish alone or are there others in the tank
  • Did you cycle your tank when you initially set it up? (If you are unsure of what this is then its a no – if interested see Aquarium Nitrogen Cycle)
  • Have you been over-feeding your fish? The amount of uneaten food rotting in the bottom of fish tank helps create toxic ammonia in your tank rapidly decreasing the water quality.

General Rules of thumb for how often to change a fish tank

  • If you keep your Betta in an unfiltered bowl then you should change 30-50% of the water every week – the smaller the bowl the more water you should change.
  • If your Betta lives in a filtered tank then you only need to change out about 20% of the water each week.

The real goal is to make sure the ammonia levels in the water are still safe for the fish, as rotting and decaying food turn into ammonia which is toxic to fish.

You may want to consider also getting some test strips which quickly evaluate your water quality to let you know if conditions are safe or in need of a change. You can find strips like these at Amazon, Petsmart or any fish store.

Items you will need for the water change:

  • 1 (or 2) buckets
    • 1 clean bucket to hold the new water that will be added to the tank. Important: make sure it has never had any sort of cleaning chemicals in.
    • A 2nd bucket for the dirty water, doesn’t need to be clean as its getting dumped.  You can even water your plants so even a watering can will do
  • A tank cleaning siphon – special siphon for draining water from a fish tank while also letting it “vacuum” the waste from the bottom – all without seriously stressing out your fish. Video below in the article of the exact siphon I use and a video on how to use it.
  • Water conditioner – used to remove the chlorine from the tap water in your house. You can find water conditioner at just about any pet store and online like Tetra BettaSafe Water Conditioner.
  • Tank thermometer (which you should already have) – to make sure the new water is the right temp before adding back in

How to change betta fish water in your tank in 3 easy steps:

Now, you don’t simply dump out a bunch of water and dump new tap water in, right? Of course not, that would seriously stress out your Betta Fish.

Step # 1 – Remove the Old Water

All of these steps are done without removing your Betta Fish. These are gentle steps that aren’t too disruptive to your fish. The only time you should need to remove your fish is for a full water change if something drastic went wrong with the tank water.

  • remove the tank cover – make sure any filters, lights or heaters that are plugged in no longer is as a safety measure.
  • get the ‘catch’ bucket close to the tank
  • remove any decorative items like large rocks, houses, etc from the bottom of the tank
  • place the suction tube or hose into the tank – some tubes have a way to get the water flowing in a siphon action simply by letting it fill with water and then shaking it lightly. If you don’t have one of these you’ll have to do it the hard way and give the end of the hose not in the tank enough of a suck to get the water starting to flow up and out. Make sure you pull it away from your mouth and put it in the catch bucket before it hits your lips!
  • Drag the suction hose across the tank gravel – what you are doing here is somewhat bobbing the the hose up and down across all of the gravel in your tank at a 45 degree angle. The reason you are doing this is it will suck up and remove rotting uneaten fish food that is collecting in the gravel, which will help make for a healthier tank.
  • Make sure you don’t remove too much water – only remove the recommended amount mention above based on your tank setup. The remaining water in the tank has necessary beneficial bacteria in it necessary for a healthy environment. Once you are done removing the tank water you can dump that water down the toilet.

Step #2 – Prepare the new water

You can start this step either at the time of cleaning or prior:

  • Fill a very clean bucket or container with water
    • use the “clean” bucket” that can hold up to the amount of water you need to replace in the tank. I use the same clean container only for this purpose, so its never confused as a cleaning bucket for household chores that may contain some sort of toxic residue from cleaners
    • As you fill try to gauge the temp – you want it as close to 78 degrees if possible. Use your thermometer to test the temp. Add warm or cool water as needed to get the temp just right.
  • Treat the water with water conditioner – our tap water is full of things that aren’t good for fish like fluoride and chlorine. Water conditioner will take care that, and it can easily be found at any pet store

Step #3 – Add the new water to the tank

  • Add your rocks or decorations back into the tank
  • Either gently pour or use the siphon to fill the tank close to the top
  • Replace or rinse the existing filter if necessary
  • Put the lid back on the tank, plug back in your filter, heater and lights
  • Enjoy!

Questions or Comments? Please let us know, we are here to help!


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