Answers for discus fish keepers from Jack Wattle, the most recognized name in discus breeding worldwide.
Plants give discus a sense of protection.

I don’t know if I should lower the fluorescent wattage..

My room for my discus depends on artificial lighting, as I don’t have any windows in the room. I am using fluorescent lamps over each discus tank and have read that you like the idea of growing live water sprite plants in some discus tanks. 1 don’t remember whether you recommend planting the water sprite or allowing it to grow floating on the surface. Because I have all my discus, as well as most of my other tropical fish, in the tank with only sponge filtration, 1 keep the water sprite growing at the tank surface.
In my discus tanks, I keep the fluorescent lights on for about 10 to 11 hours daily and have done so for the past year. It’s necessary for me to give “haircuts” to the water sprite at least once a week. If I don’t do so, the plants will be 3 to 4 inches deep at the tank surface.

My discus are very much at ease with all this overhead plant growth, but is it best to keep the growth at 3 to 4 inches on the surface, more or less, or perhaps lessen the growth some? I don’t know if I should lower the fluorescent wattage—it’s now 60 watts. What do you think? I can reduce the lighting to 40 watts.

Duane Sutter
Dover, Delaware


Your letter is very interesting. 1 wish you had told me something about the tank water pH, temperature, and hardness and where your water comes from. Is it necessary for you to condition the water before using it? And how about the volume and frequency of water changes in the tank?

The water sprite (Ceratopteris) that you have is veiy hardy and will thrive in most aquarium water, so I am assuming that your

discus are doing as well as the water sprite is doing in your water. And it will be no problem to reduce the lighting from your current 60 watts to 40 watts. Is the present light system fu11-spectrum lighting?

Have you given any thought to replacing your fluorescent lighting in at least some of your tanks with LED lighting? The LED lights manufactured today have a lifetime of more than 16,000 hours, and they use a fraction of energy compared to your current lighting. I use LED lights over discus tanks as well as over the terrariums for my small frogs from South America and Madagascar.

As you know, with overhead lighting and an aquarium plant such as Ceratopteris, plant growth will be heavy. When I visited discus breeders in New Zealand, most had water sprite growing very nicely as a floating plant. All discus accepted their very nice looking security blanket at all times. Why not try something in one of your discus tanks: allow the sprite to continue to grow. This is assuming that the tank is at least 50 gallons or so.

Whether you know of any other live food that 1 can feed the young discus..

I’m having good success breeding my discus, and the young, while still feeding from the parents’ sides, are also accepting newly hatched brine shrimp. My question is whether you know of any other live food that 1 can feed the young discus while they are at that age of eating the small shrimp? I have no difficulty in raising the shrimp, but I'd like to also be able to feed them another very small live food if it is available.

Walter Callahan
Auburn Hills, Michigan


Yes, there is a small live food that your young discus will accept and you should be able to cultivate easily: Collembola, commonly known as springtails. When full-grown, they are approximately 2Vi to .3 mm in size and white in color. They are veiy easy to breed. I raise springtails for my Mantella frogs from Madagascar, and l know of no food for fish or frogs that is easier to raise.

I maintain (he springtails in clear plastic containers, the type used in supermarket delis for potato salad, hummus, cottage cheese, etc. Place approximately Vi inch of charcoal or carbon in the bottom of the container—the type of charcoal used for potting orchids, for example—and thoroughly wet the charcoal with distilled or spring water. Add the initial Collembola culture to the container. You can feed your springtails brewer’s yeast by sprinkling the food lightly on top of the carbon pieces. Feed the springtails every few days, and take the container lids off only during feeding.

After the first culture has begun to reproduce rapidly, which should take several weeks, obtain five or six additional containers and begin to sub-culture from the first container. Keep new cultures going at all times by not feeding each time from the same container. To feed your discus fry, first turn off filtration, hold a large piece of springtail-covered charcoal, and swish the springtails off the charcoal into the discus tank. Return the charcoal to the plastic container, and your feeding is done!

Discus maintain a rate of activity..

Among my many tanks of both marine and freshwater tropical fish, 1 have eight tanks that are for discus only. It is not necessary for me to spend any more time in caring for these discus tanks than for any of the other tanks. But from time to time, when 1 have an extra minute or two to view my discus, it appears to me that the discus, for whatever reason, are not as active during those moments as they are at most other times. Do your discus maintain a rate of activity that is more or less the same every day? I haven’t added any medication to any of those discus tanks because the fish don’t appear to be sick.

Amy Campbell
Columbus, Ohio


You and all other discus hobbyists and breeders must have some basic knowledge of the natural behavior of discus in order to determine if your fish are sick in any way.

Yes, my discus, at times, are not as mobile or active as they are the majority of the time—nor am I as active at all times. Are you? Discus are not pelagic, so we can’t expect them to be moving about much in their tanks at any time. I have found that when discus pairs are in their spawning periods, they will control no more than approximately 20 percent of the tank, and when they are not defending eggs or young fry, they don’t defend much more tank space. At other times, they don’t appear to be moving at all.

Aside from those times when the discus are indeed active, such as during their spawning periods, you will probably notice that they will increase their activity if a new addition is made to the tank.

Once again, activity can generally be observed with all tropical fish at feeding time. When feeding, if you offer a larger-than-usual amount of a food that your discus find very acceptable, you will immediately see that as their metabolism rises, their level of activity will rise as well.

TDS (ppm)
Micromhos (ppm)
Calcium carbonate (ppm)

This feeding action can result in what lochs like vigorous fighting among the discus in the tank, discus that at other times are amiable enough and show no aggression, except at feeding times.

So, Amy, Til wrap this up and say that your only worry should probably be whether or not your Ohio State Buckeyes can go undefeated again this year in football!

Water for small discus fish..

I have a question about the water I expect to use after I purchase a large number of small discus from a breeder who is about 125 miles from my home. I have what you refer to as grow-out tanks of about 35 gallons each, where I plan to keep about 25 small discus per tank.

The breeder uses about 75 percent tap water with 25 percent reverse-osmosis water in all his discus tanks. He told me that this water was about 25 ppm of total dissolved solids. Am I right to assume that this is hard water? Do I want to keep these young discus in the same type of water that I have?

Richard Donaldson
Oceanside, California


Not knowing anything about your local water, I can't answer (hat last question. Did you get a reading of the pH in the breeder's tanks? If not, then please do so. And before you part with any money, sit down with the breeder and, with pen and paper or a recorder in hand, ask as many questions as you can think of.

The breeder's TDS (total dissolved solids) reading tells me that, yes, his water is hard. And before I forget, get yourself an inexpensive hardness kit plus a pH meter or kit. 1 am including here an easy-to-read chart that, combined with your hardness meter, you can use to establish the water hardness.

If you manage to keep the readings generally between 75 and 125, you shouldn’t have problems. Additionally, water changes, optimally 40 percent daily, will be beneficial to your discus. If you want to get excellent growth on the young discus, you might want to skip mixing reverse-osmosis water with your municipal water until the young fish approach adulthood, at which time you could probably maintain a micromhos reading of approximately 75 to 125.

I have a very good friend, a discus breeder, who gets maximum growth on his young discus by using 100 percent well water from a 65-foot well with a steady TDS reading of 545 ppm. If we both have discus hatchlings at the same time, his free will sustain more rapid growth than my fry will exhibit.

Jack Wattley is worldwide the most recognized name in discus breeding. Breeder, judge, collector, scholar; Jack is the foundation on which modem discus keeping has been built. He has been sharing his experience and knowledge— and the discus he breeds—with aquarists throughout the world for decades, and just one of his many awards was his recent Lifetime Achievement award from the ACA. Long frost the age at which most people retire, he still serves as ambassador of discus and goodwill across the planet.