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Keeping Discus- the Basics

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There was very little known or written about discus until after the middle part of the 20th century, and it wasn’t until around the 1960s that hobbyists in various parts of the world began breeding wild-caught discus. After that time, a good deal of information began to emerge about keeping and breeding these marvelous fish. In the 1970s and 80s, there was a proliferation of breeders who established discus fish farms for local and export sale, mainly in South East Asia and some parts of Europe, particularly in Germany. By 1990, many new and colorful varieties of this intriguing fish had been developed, and the hobby was in full bloom in North America.

Discus are one of the most graceful, interesting, and arguably the most beautiful of all freshwater tropical fish. The fascination of keeping and raising these magnificent fish has taken the aquatics world by storm, and you’re one of the many wanting to get started with this very satisfying hobby.
This guide is intended to get you started on the right footing – to enable you to raise the “King of the Aquarium” in good health, with the least amount of start-up snags and problems.
Here’s how to get started!


Discus are relatively large fish, growing to 6 inches or more at maturity, measured from nose to tip of tail, and therefore require a good deal of tank space in order to reach their potential and thrive. I recommend you start off with the largest tank you can afford. This should be no less than 55 gallons, but more preferably in the 65 to 75 gallon range. If budget is a problem, buy a used tank. There are many to be found on Craig’s List in the United States and Canada.


  1. Heating

Discus require a temperature range of 82 to 86 degrees Fahrenheit in order to thrive. You’ll need to acquire a heater of sufficient wattage to maintain the desirable temperature for keeping your discus, in accord with the size of your tank. As a guide, 4 or 5 watts per gallon should be sufficient– so a 250 watt heater should do nicely in a 55 gallon tank. Many heaters only have a maximum temperature setting of 86 Fahrenheit, it will be very difficult for such a heater to achieve and constantly maintain water temperature at the maximum setting level, particularly if your tank is uncovered or partially uncovered. It is best therefore to get a heater with a maximum setting level of 93 Fahrenheit. There are a number of reliable makes on the market, so you will have a good selection to choose from.

  1. Filtration

There are three types of filtration, i.e. biological, mechanical and chemical.

  1. Biological filtration refers to the breakdown of toxic ammonia and nitrites, and then into nitrates by a colony of bacteria. These bacteria are often referred to as ‘beneficial’, or ‘nitrifying’ bacteria.
  2. Mechanical filtration refers to the process of removing solid waste matter and other particulates from the water column. Examples include foam pads and flosses.
  3. Chemical filtration removes chemical impurities and discolorations and clarifies the water. Carbon is often used for this purpose.

All three types of filtration can be maintained, or ‘housed’ if you will, in the actual filter container types that you select for your tank, whether that be a Hang-On-Back (HOB), or canister. A sponge filter will provide for biological and some mechanical filtration. Your colony of beneficial bacteria will establish itself in or on tank surfaces, but primarily on and within whatever filter media you elect to use in your filtration container(s).
There are many reliable types of filters to choose from. Many, if not most, discus keepers raise their fish in bare-bottom tanks and they usually employ one or more sponge filters, often supplemented by either HOBs or canister filters, to provide for all their filtration needs. In a planted tank, the preference seems to be to use either HOBs, or canisters, or both together, and to forego sponge filtration, primarily for aesthetic reasons.
The size of the tank, its purpose, and your preference will determine the needed type, size and capacity of the various filters which are available to choose from. Capacity is measured by the volume of water turned over each hour. A complete turnover of at least four times an hour is suggested as being suitable. An example of adequate filter capacity for a 55 gallon tank would be to use a filter rated for tanks up to 70 or 80 gallons, and which has an average water flow rate of 200 or more gallons per hour. This will result in a complete water turnover rate in the tank of approximately four times an hour.

  1. Test Kits and Other Essentials

One of the most important items of equipment you will need are test kits to test your water on a regular basis for the presence of ammonia, nitrites, and nitrates, and to determine the Ph, and general and carbonate hardness levels.
While your local fish store (LFS) will very likely provide a water testing service at no cost to you, this can be quite inconvenient. With your own test kits, you will be able to quickly check your water parameters at any time. This will allow you to ensure your ongoing tank care is being maintained as it should, and to determine if your water is the culprit should problems occur.
Once your tank is fully cycled and ready to house fish, the test for both ammonia and nitrites should read “0”, and nitrates should be less than 20 milligrams per liter (mg/L). Your Ph test should reflect a steady, stable maintenance of Ph anywhere between 6.0 and 8.0. For discus-keeping, your water’s General Hardness (GH) can suitably be anywhere between a low of “0” to a high of 200 mg/L, whereas Carbonate Hardness (KH) should generally be between 40 and 100 mg/L.
You will also want to equip yourself with other essential items, such as a water conditioner to remove chlorine, chloramines, and other undesirable elements from your tap water. A water conditioner should be used at start-up when cycling your tank, and whenever replacing water during water changes.
Other needed items are a thermometer, fish net, siphon hose, five gallon bucket or pail for water changes, sponge, scrub brush, perhaps a water barrel for ageing water (a food-safe garbage pail will do), extra filter media items such as filter floss, foam pads, etc. and of course, some fish foods. If you’re doing a planted tank, you’ll need substrate, plants, driftwood and/or rocks, etc.
Once you have decided on the size of your tank, you’ll need a sturdy stand to carry the weight. A filled tank, with substrate, driftwood, etc., will average around 10 lbs. per gallon, so a 55 gallon tank will weigh over a quarter of a ton. Buy a ready-made stand that is specifically designed to maintain the weight of the type and size of tank you are getting or, if you are going a home-made route, get some expert help to ensure it is properly braced and structured to accommodate the weight.
As for lighting, you won’t need extra strong, bright lighting for discus. Low light will do, perhaps in the range of around one to two watts per gallon. For a planted tank, this should prove adequate for many, if not most, of the hardy, easy to grow plants that will also tolerate the higher temperature you will be maintaining for your discus.


Bare-Bottom Tank
This set-up is by far the most preferred approach by both newcomers to the hobby and experienced aquarists alike, for “growing-out” juvenile discus or for keeping adults. It is generally regarded as the easiest for maintenance purposes, and the most successful way of keeping discus. It allows you to readily spot any build-up of uneaten food, fish feces, or other matter, and quickly siphon it off at any time. It makes it easier to undertake more frequent and larger water changes to promote better and quicker growth of juveniles, to maintain a high level of water quality at all times, and to more easily clean tank glass, as well as to service or change equipment. A bare bottom tank is easier to medicate if that should ever prove necessary.




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