Most Important task to a healthy tank?

[MiddletonMark]

The most important thing IMO is between two things:
--dedicated husbandry to tank [regular w/c, water testing, etc]
--self control. [avoiding overstocking fish, bringing home incompatible livestock, taking stocking slowly + building the tank for the future]

 

[davocean]

Most important is just what you did.
Research and ask questions from as many experienced people as possible b4 doing anything.
Next is regular maint/water change/ and lots of observation.
No more hermits in my tank
LOTS OF SNAILS
Good circulation and skimming is huge