Design your self-sustaining setup.
Answer five questions. The planner checks your choices against 87 real species records and returns a balanced build with a will-it-balance read: green, amber, or red, and the exact reason. Running it is free.
What the read actually checks
For a tank or pond, two species can share water when their temperature, pH, and hardness ranges overlap. The planner reads those ranges from the database and finds the overlap. For a vivarium it runs the same check on temperature and humidity. When your stated plan does not fit your conditions, it tells you why and returns the closest build that does, rather than selling you a setup that will crash.
It does not replace judgment, and it does not diagnose a sick animal. It gets you to a balanced starting point, which is where most first tanks go wrong.