Fish die in new tanks because ammonia and nitrite build up invisibly, and no amount of feeding or decorating fixes that. These articles explain the nitrogen cycle, how to run a fishless cycle before any fish arrive, and how to read a test kit so you catch a spike before it kills anything. This is the science every keeper needs by week two. Water changes, ammonia control, and nitrate management all live here, from your first cycle through routine maintenance.
Start here: How to Cycle a Fish Tank.
