Why do aquaponics systems fail and is it harder than hydroponics?

Aquaponics is generally harder than plain hydroponics because you are managing two living systems, fish and plants, plus the bacteria that link them, and a problem in any one can cascade through the whole setup. Common failure causes are: power or aeration failure killing the fish, which then collapses the nutrient supply; water quality going wrong, ammonia or pH swings stressing fish or plants; an imbalance between fish load and plant uptake, fouling the water or starving the plants; disease in fish or plants spreading through shared water; and the fact that you usually cannot use strong chemical pesticides because they would harm the fish, so pest control is constrained. The biofilter bacteria also take time to establish, and rushing that early stage causes crashes. Underneath most failures is insufficient understanding of how the three components interact. It rewards a patient operator who learns the balance and protects power and water quality. If you want the simplest entry to soilless growing, hydroponics is easier. Learn aquaponics hands-on at a working farm before investing.