PLEASE NOTE: I have updated this description due to some of the negative reviews. I had been asked for several years by Discus keepers for a quick guide, featuring the key points in a summary form. This book and guide is exactly a "Quick Guide" and the information is accurate, covering the key factors for a Discus Environment. I successfully bred Wild Discus in captivity and use to exchange ideas with colleagues and friends including Jack Whattley and Dr. Eduard Schmidt-Focke. In fact, my other books are very comprehensive and have some pictures given to me by Jack and Eduard. When successfully breeding Discus and rearing different strains, in the 70's and 80's, one of the key factors was "Water" and risk aversion, keeping it simple, along with many others, but changed water on mass from our taps, as I was on most days carrying out water changes in my fish house amounting to 3 to 4,000 gallons a day. Tap water was used, and was chlorinated, and the small amount of chlorine that dissapates in a few hours serves to keep fish disease free, also keeping amonia and nitrate levels down even further. My biggest frustration over the years is that many Hobbyists and Aquarists get carried away with commercialism in the way of products. The biggest mistake Aquarists make is trying to change their water to the believed needs of the fish from articles written. Whereas the secret to breeding these majestic species, symphysodon (Discus), is to acclimatize the fish to the water, so you literally have water in massive amounts on tap literally! Many articles written over the years, especially in recent times are commercially driven and related to keep publications in existence, and most of the articles are nonsense, written by novices. The key to keeping Discus is risk aversion like I said, and this is pointed out in all the other books I have written over four decades. The Discus Book Second Edition for example, is one of the most comprehensive books ever written to date on the subject. All the reference point covered in the book are based on first hand experience. Regrettably, all I can do is try to accommodate every Aquarist, all of who have different expectations with varying experience. This is as I say a quick guide, but covers exacting conditions and temperatures etc. Best Wishes, Alastair R Agutter Author Keeping Discus Fish Quick Guide Book, has been written by the author after many requests by hobbyists, and novices, taking up the keeping of Discus (symphysodon) Tropical Fish, as the preferred species they wish to successfully keep. The Discus is a highly evolved and very intelligent species, and there are certain golden rules and methods found in this book, that Aquarists need to adhere too, and apply, when successfully keeping these majestic beautiful species in the interests of their welfare. The Guide Covers: Discus Fish Origins, Discus Fish Aquarium Sizes, Buying Discus Fish Advice, Discus Water Conditions, Discus Fish Filtration, Discus Fish Water Temperatures, Discus Fish Feeding Routines, Discus Fish Diseases, Discus Breeding and Spawning.