Massive Discus Growth – Jack Wattley Experiment

Massive Discus Growth

Back in 2002 at the American Cichlid Association annual convention, I sat in the front rows with my video camera to watch Jack Wattley, a man who needs no introduction in the Discus world.

Mr. Wattley went on to share one of the single most important trade secrets to explosive Discus growth that he discovered in his experiments with Discus.

In this article I will try to recall from memory what was shared that evening as well as reference from articles later written by Mr. Wattley.

The Experiment

To the best of my knowledge I will try to recall exactly what Mr. Wattley said, as well as reference my notes and if I can find the video footage I recorded will update this article accordingly.

Mr. Wattley took small Discus from the same birth batch and split them into two groups and placed each group into small tanks. If I recall correctly the first tank was just large enough to place a pitcher in the tank to remove water.

The smallest tank had no filtration at all, and 90% of the water was changed seven to eight times a day.The second tank was a bit larger and contained a sponge filter. The water was changed once a day and 90% of the water was removed each time.

After about a month the results spoke for themselves. The siblings in the smaller tank that received seven to eight water changes a day with no filtration were double the size! Even though they were born from the same batch of fry, same parents and ate the same diet, the extreme water changes resulted in double the growth.

What’s In The Water

How can water contribute to explosive Discus growth? What exactly is in the water, or more importantly what exactly was removed? The obvious answer is waste and uneaten food was removed and fresh oxygen rich water was consistently introduced.

Many believe that tank size alone will produce larger Discus, but when I listened to Mr. Wattley share his discoveries it simply made all the sense in the world. Quality of life and pristine conditions enabled the Discus to grow to their fullest potential without debilitating toxins and bacteria that would stunt development and growth.

It is the same reason professional athletes feed themselves the purist of foods, vitamins and supplements. Along with training they also make sure to get plenty of sleep and avoid toxins to the system like drugs, smoking or alcohol. Some athletes go as far as moving to the country side while training in order to remove themselves from the stress of city life and allow for full focus and recovery from training.

Beneficial Side Effects

Now of course changing water seven to eight times a day at 90% rates is a bit extreme, but if we look at what that benefits this allows it is really eye opening.

With more water changes Discus are allowed to eat more often and as much as they please. No excess food accumulates to create ammonia spikes or other harmful side effects. By consuming more proteins and nutrients the Discus can feed the teenager like appetite that growth spurts demand.

With more frequency also comes the opportunity for more variety and thus more nutrients and proteins for growth. Its a beneficial cycle that is geared for optimal health and growth.

Genetics Over Several Generations

Now I do not have any formal training or education in genetics so please take what I am about to write as just simple food for thought.

All living things evolve over time to meet the needs of their environment. If they do not there really is only one other alternative… death. In the animal kingdom certain animals are muscular to capture and kill their food, others are long and limber to escape capture.

Humans are similar when separated into regions and viewed in the sense of evolutionary growth. In some countries it is pretty common to have most people well over six feet tall and in other countries being over five feet tall is an awe inspiring sight.

The point of this thought is if Discus are given pristine environments to reach full potential of growth and development wouldn’t they produce similar offspring? Selective breeding has been going on for years for color and shape. But what if the key to size is focus on optimum nutrition and pristine conditions? More experiments should eventually conclude this true or false.

Questions For You

Have you visited an American Cichlid Association convention?

Do you agree with Mr. Wattley’s experiment?

What do you believe is key for Discus growth?

9 thoughts on “Massive Discus Growth – Jack Wattley Experiment

    • Hey Adrian,

      I have seen sand used and sand like substrate used in planted tanks that contained Discus. I don’t think it would be recommended to use Marine Live sand in a freshwater setup as I am sure it’s for salt water purposes only.

      The ideal setup for Discus if you are interested in breeding and showing is a bare tank with no substrate. If you are to use substrate and want a sand like appearance look for planted tank substrate. In my experience though I will warn you that planted tank substrate contains fertilizers and properties specifically to induce plant growth. If you are not going to have a heavily planted tank you may induce the growth of algae, and lots of it.


    • Hi Phil,

      Yes Discus can eat bloodworms and several other pre-packaged frozen foods. I like using Hikari brand bloodworms and also feed Krill and a veggie mix.

      If you want to try live foods I would suggest California Black Worms:

      California Blackworms will make your Discus grow super fast but it is more work keeping the worms clean and alive versus using frozen pre-packaged food.

      Hope this helps!

  1. I agree with the premis that clean, fresh, oxyginated water changed frequently will inspire not just growth but optimum health! My question is: I am going to set up a 225 gallon tank for Discus fish. How does one perform those – or any multiple changes – in a day? Pariculary if working to make more $$ to maintain said hobby /fish? 🙂
    Possibly, two changes a day may be challenging but that may be the only alternative. Plus, how many discus fish can a tank of this size comfortably handle?
    Thank you,

  2. Not too sure I agree with the ‘Limiting Health Hormone’, concept promoted by some. In the wild, the current would undermine the effectiveness of this hormone. Originally discovered when studying tad poles, this theory has been advanced, to include Discus.

    I think the ‘typical hobbyist’, should not keep Discus and avoid the ‘Discus Trap’. Expensive to purchase, maintain ($30x5x-6x), and laborious to keep (lots of w/c s- support tanks & equipment, as well as expensive foods-CBW), and ultimately hard to keep stress free, they are virtuously impossible to diagnosis and effectively medicate, for the average owner.
    To over simplify the keeping of these magnificent fish, will only lead to disastrous results, frustration, heart ache, and desperation.
    The chances of creating the perfect environment and being rewarded with having healthy, long live Discus is remote.
    Breeders and others may not address this situation, because of the business aspect. This is typical of breeders of parrots, and many other pets. The emphasis on what it takes to maintain these pets, and the commitment, of money, time, and dedication is rarely addressed.

  3. Randy,

    Conversely, I also do not thing we should scare people away from discus keeping either. I have been keeping and breeding (not for profit) discus for 30 years and they are certainly no more difficult than the critters in my reef tank. They are not for a casual hobbyist, but anyone with a serious and enduring interest in fish keeping, who has some previous experience with other fishes can do alright. Diagnosis is not so difficult, especially if you have a microscope, and know a little about common discus ailments. So if you are ready for a challenge, I say, go for it!

  4. I have few quistion on Discus Breeding. Besically I am a Crazy discus hobbyist from Kolkata India. I study on Discus for last 4 years. though I am keeping Discus for last 12 years. Before that Breeding was not my concern I love to grow Discus thats all to me. But now when I am going to breed Discus some quistion is comming out from my mind. At many place I have seen Discus should breed in RO water. but I have seem most of the Big breeder dnt think of a RO or such thing. anyway I used to keep my Discus in Normal Tap water with Anti Chlorine(Sodium Thao Sulphate) my water TDS play from 102-130 ppm. ph gives lil high 7.9-9 so my Quistion is In this water parameter may I able to breed Discus properly ??? Here I want to say I grow most of my collection in this Water Parameter from 8mm body size means from the age of 10-12 days. Lastly I breed but everytime I dnt getting fry as Quantity I seen at eggs. it defer from 50-70 hardly. And many time I observed Pair are not laying eggs even for a long.

    my 2nd Quistion How many Times I change the water at Breeding Tank? Or npt even change?

    I used to feed Mosquito Larva to my big Discus along with Goat Heart mix. is that good Enough. ??? Cause I cnt get fresh Blood Worm so I culture Mosquito Larva. as this is can form in Clean water easyly.

    What about feeding style? I used to feed 8 times a day. to all my fishes. and to Breeding Pair at Breeding tank once a Day Mosquito Larva. as Goat Heart can spoil maximum water.

    How to protect Eggs from Fungul infection? I used Dry Methilin Blue and Make Solution with water and spray on d Egg. but It dnt work. as I dnt know the ratio of Methilin Blue and Water in the Solution to get perfect solution.

    I also tried formalin Drops to protect eggs properly but Even I see fries comming and getting in Fungus net and dieing by getting white.

    Please I need your help to solve all these problems.

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