The “Golden Rules of Fish Keeping”

• Quarantine ALL Your New Fish.
• You Can Never Have Too Much Filtration
• Poor Water Quality is the Trigger in 95+ Percent of Fish Illness.
• Don’t Panic When Fish Are Sick; You’ll Overreact and Overmedicate.
• Never Deploy A Treatment Before You’ve Diagnosed Your Water!
• Word to the Wise: Under-crowd and under-feed For Almost Effortless Success.
• Understanding the Pond’s “Nitrogen Cycle” is as Important as Understanding the Role of Gas and Oil in Your Car.
• Always Ask About the “Downside” When Talking With Marketing Reps.

I am sure there are other things that I’d add over time. Things I’ve said over and over again. The above list is pretty complete with ideas to live by, representing some of the most fundamental shortcomings of the average hobbyist.