13 Reasons Why My Discus Darting & Dashing – Dashing Discus Cure


Discus is darting and dashing around in the tank or aquarium (Sometimes Discus Jumping out of the tank) because they are under a lot of stress resulting from a number of reasons such as poor water conditions, irregular water temperature, and because they are being bullied.

Table of Contents

Discus Darting Symptoms

  • Loss of appetite.
  • Discus clamped fins.
  • Discus fish swimming straight up and down.
  • Discus swimming fast into the sides.
  • Discus dashing around the tank.
  • Discus jumping out of the tank.

13 Reasons Causes Discus Dashing

There are many reasons why Discus fish might behave like crazy and start dashing in the tank including:

[1] – Stress Caused By Improper Water Conditions

Discus is a fragile breed of fish, and little changes in its environment, such as poor water conditions can bring on a lot of stress.

[2] – Ammonia Concentration And Nitrite In Tank’s Water Should Be Zero

If the water in the tank contains even a little amount of nitrite or ammonia which are both dangerous to your Discus (could kill your Discus), the Discus will be under a lot of stress and will be struggling to breathe because the oxygen level will drop.

[3] – An Abrupt Shift In pH Level Of Tank Water

This can also prove to be quite stressful for Discus, and the Discus could end up dashing around the tank or swimming fast into the sides, or even jumping out of the tank.

The build-up of ammonia could result from waste products excreted by the fish in the tank or from foods that were not eaten and then decayed.

NOTE: This is why I recommend that water in the tank should be changed regularly and the tank should be cleaned before the water change.

It is important to perform regular 25-30% water changes weekly, so the tank or aquarium can be healthy and in good condition.

[4] – Wrong Temperature Of The Tank’s Water

It is another issue that could lead to stress for your Discus. When the water temperature is constantly fluctuating, it could render Discus fish swimming straight up and down the tank or darting.

NOTE: When the water temperature is not maintained, the amount of stress it brings to aquarium fish is quite much, keep your water temp. between 82º F – 84º F.

[5] – Parasite Attacks

This can be stressful for fish. The parasites could either be worms or protozoa, they weaken the immune system of fish and it could be one of the reasons why some owners report that they observed their fish darting around the tank and then dying.

[6] – The Number Of Fish Stocks In A Tank

When it comes to deciding the quantity of Discus fish as well as the plants and objects to have in a tank, you should be careful not to put in too much.

When there are too many plants or objects in a tank packed with a lot of Discus fishes, it will prove difficult to manage the tank appropriately (clean the tank and change the water).

Too many fishes in a tank basically mean more waste which means more ammonia build-up which will damage the integrity of the tank water, and affect its pH level as well. If the decorations or objects in the tank or aquarium have sharp edges, they could be hurting the fish, and the wounds could become infected – an infected fish is a stressed fish.

[7] – Discus Being Bullied

If Discus is being bullied or there is competition for food which leads to fighting, they will end up being stressed, causing them to swim frantically in the tank.

[8] – The Presence Of Chemicals In The Tank Water

You have to make sure that the water in the tank is chlorine-free.

There are some areas where chlorine is added to water in order to kill germs and chlorine is hazardous to fish, especially Discus (it can kill your Discus fish).

NOTE: I recommend that you buy a test kit for the water you want to use to determine its contents.

Medication that is added to the fish tank also contains chemicals, and although they can treat a diseased fish, it could be harmful to other fishes in the tank.

NOTE: It is advised to quarantine a sick fish first before administering treatment.

[9] – Diseases Due To Improper Diet

When you do not know the proper diet for your Discus, you are likely to use any amount and type of feed, and that will stress the fish, making it vulnerable to either parasitic attacks or diseases.

[10] – Loud Noises

Tanks should be kept in places where there are no loud noises, furthermore, when Discus is in a new environment, they need some time to get used to it. If they are not used to being around humans, a shadow can scare them, causing them to go Discus crazy, wild dashing around the tank, or even jumping out of the tank.

[11] – Banging On The Tank

If little children or kids bang on the tank, this will make your Discus fishes dash swimming in the tank, avoid that.

[12] – The Hardness Of The Water

Discus prefers soft water; if the water hardness is not appropriate, it will impact greatly the condition of the fish.

[13] – Sudden Lights Changes

Sudden light changes will make your discus dash and dart or even try to jump out of the tank, try to keep your room lights steady all the time.

Discus Darting Treatment Steps

[STEP1] – Carry out a 75 percent water change after cleaning your tank.

[STEP2] – Add Carbon To Your Filter

Throw some carbon in the tank filter to remove any chemicals that could irritate the fish.

[STEP3] – Use a UV filter

Use a UV filter to kill the bacteria in the tank.

[STEP4] – Maintain Aquarium Water Temperature

When the temperature of the tank water is too high or too low, it can be stressful for your Discus.

NOTE: Maintain the water temperature around 28º C – 30º C (that is, 82º to 86º F).

[STEP5] – Use Novaqua Plus

Apply Novaqua plus to the tank after changing the water.

Novaqua plus

[STEP6] – Use Tetra AquaSafe

Add Tetra AquaSafe of any alternatives of Anti chlorine to remove chlorine from the tank’s water.

The presence of chlorine in the water will burn the gills of the Discus, and it will be darting around the tank.

NOTE: Adding Tetra AquaSafe to the tank water will cause the chlorine to evaporate out of the tank.
Tetra AquaSafe

[STEP7] – Test Your Tank Water For pH, Ammonia, Or Nitrite Level

It is difficult to maintain the pH level of tank water, observe your tank for any abrupt rise and fall – the pH level for Discus is 7.0 so you can maintain the pH level between 6.5 – 7.0, but they will survive between 6.2 and 7.8.

NOTE: Changing your aquarium water weekly will assist in keeping your water in good condition, but you should always use your water test kit after every water change.

[STEP8] – Maintain Water Hardness

Grind peat and driftwood to make tank water hard. Be sure to add them to the water filter or directly into the tank.

Peat Driftwood

[STEP9] – Maintain Stable Lighting

Allow for lighting in the tank for a long period of time. Do not turn off the light until at night; this makes sure that there are no shadow movements.

NOTE: Aquarium light should be used a maximum of 5 to 6 hours to avoid algae build up in the tank.

Discus Darting Future Prevention Tips

  • Change the water in the tank regularly. Make sure to clean the tank before any water changes.
  • Do not overstock your tank with fish, plants, or objects.
  • Avoid overfeeding your fish. Food not eaten decay and lead to a build-up of ammonia.
  • Cycling a tank while Discus is in it is deadly. Discus is fragile, and that is why it is recommended that you do not add the fish to a new tank when the nitrogen cycle is not yet complete. Give a period of one month before you introduce a new Discus fish into your tank – the nitrogen cycle takes not less than one month to be complete; it is also recommended that you perform regular water changes during this period. Change 40% of the tank water every five days.
  • Spend a lot of time in front of your fish tank; this will help your Discus become accustomed to having a human presence.
  • Avoid anything that might startle your fish.
  • Keep your children away from your fish tank. Loud noises or banging of the tank could be stressful for Discus.
  • Chlorine is dangerous to Discus when you give it a few days before turning the water into the tank, the chlorine will age out. An alternative is purchasing a de-chlorinator from any pet store if you want to use the water immediately.

Darting Discus, What Does This Mean?

Darting Discus means that Discus is stressed because the condition of the tank water is poor; they are startled, competing for food with a larger fish, fluctuating water temperature, and overstocked tank.

Why Does My Discus Fish Swim Up And Down The Tank?

Discus fish swims up and down the tank when they are stressed, and that is an action meant to alleviate that stress.

The pH level of the tank water might have shifted, or there is a build-up of ammonia or nitrites, or the temperature of the water could constantly be changing.

Discus Fish Swimming Frantically In Tank

Discus fish swimming frantically in the tank is a resultant effect of stress due to poor water conditions (ammonia build-up, fluctuating pH level, nitrite level), irregular tank water temperature, overcrowding, and parasitic infestation.

When the source of stress is not quickly identified and treated, it will lead to diseases such as fin rot, dropsy, swim bladder, etc.

To mitigate the cause of stress, test the tank water ammonia, nitrite, and pH levels as well as the temperature, then change the water, and observe the behavior of your Discus.

NOTE: If this does not solve the problem, consider consulting your vet.


Discus darting and dashing around in the tank is a response to stress. Poor water conditions, overstocking the tank, overfeeding, and fluctuations in water temperature are some of the reasons why Discus can be stressed. It is important to identify the stressors and remove them before they deal any more damage.


This is me Firas Sameer, the founder of DiscusRescue.com, I am an aquarist guy with a passion and love for Discus fishes, I am learning every day with my hobby at home and sharing the things I am learning from my experience with you.

8 thoughts on “13 Reasons Why My Discus Darting & Dashing – Dashing Discus Cure

  1. I just came across your website and as a newcomer to the discus hobby it is really refreshing to get your expert advice on these beautiful fish. I have a question with regards to discus – spinning or whirling disease. This is where the discus would swim in a circular motion and run into the glass of the tank. This is similar to darting as in your article. This is sometimes fatal to the fish and i was wondering if there is any specific treatment you would recommend in the event this happens.

    1. Sometimes fish diseases become fatal if they do not treat in the proper early stages, that’s why as an answer “yes” it could be fatal, however, you could follow the instructions in this article on how to treat your Discus.

  2. Hello I really need help with my red panda discus. She is dashing around the tank but the tank is cycled checked for ammonia, nitrite, nitrate and they are all at 0 PPM. I put an anoxic filter which also helps clean the water and that seemed to ease her nerves a little because she only did it once. She is trying to tell me somethings wrong but I don’t know what it could be I treated them with flubendazole, prazi pro 3 weeks ago and all were eating till suddenly one day my one discus were dashing everywhere and she will go into shock and she will stop breathing! Again NO AMMONIA NO NITRITE OR NITRATE I clean this tank regularly 50% a day to make sure there is no nitrate and I have 4 discus in a 40 Gallon breeder she is the biggest discus of my tank and she is the bully but she is very weak. I had to seperate her because I am trying to see what i could do I would appreciate some help!

    1. Hi Abraham, first of all, it’s not good that you change 50% of the water every day, we do this sometimes for 2 to 3 days for a very specific treatment and not as a normal daily operational action, the second thing is there are many factors for why your fish is darting or dashing, it could be a wrong tank placement, it could be a light in the room or tv in front of the tank that changes its lights from the screen, it could be also a disease or in proper water parameters, you could also check the water temperature try to increase it to 34c or 36c .. other reasons you could find it in this article.. so in order to heal your fish you need to identify the exact cause of it, I do not know all the details because I am not there with you. I hope you could save your Discus fishes and provide them with a perfect envirounemts.

  3. I have a 55 gal with 7 discus fish 2/3.5 in they were just put in my tank two days ago. They are stressed out swimming up and down and not eating. Checked everything keep my tank very clean temp is at 85 no ammonia but nitrates are up ph is at like 7.5.. water change twice a week 20% how can I calm them down worried they will die. Looking for answers.. thx..

    1. You may refer to this article and compare to your case which of the reasons are causing your discus to be stressed:


  4. I¡¦m not positive where you are getting your information, however good topic. I needs to spend some time learning much more or working out more. Thanks for excellent info I used to be searching for this information for my mission.

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