To complete Lullaby Mastery in Fisch, you need to finish three parts in order: keep all Lullaby modes active for 3 minutes, then during a starfall perfect the metronome and perfect-catch a prismatic fish above the clouds, and finally gather the six required fish and use them to open the final portal.

Steps

  1. Activate every Lullaby mode except the new one and keep them running for 3 minutes. A group of friends makes this much easier because you can coordinate the modes together.
  1. Wait for a starfall and then complete the timing challenge by hitting the metronome perfectly. At the same time, perfect-catch the prismatic fish above the clouds.
  1. Catch the six required fish:
  • Prismatic Harmonic Dove.
  • Prismatic Ancient Deep Serpent.
  • Prismatic Mythic Fish.
  • Rainbow Void Glow Ghost Fish.
  • Rainbow Ancient Kraken.
  • Rainbow Anglerfish.
  1. Use Traveler’s Whistle if you have it, go above the clouds , hold each of the six fish in your hand one by one, and click them so they float around you. Once all six are floating, the portal opens.
  1. Walk through the portal , go up the stairs, and reach the top to finish the mastery.

Fastest approach

  • Do the 3-minute mode requirement with a party so nobody has to juggle everything alone.
  • Save your starfall step for when you already have the right setup ready.
  • Pre-catch the six fish before starting the final portal step, since that part is mostly about collecting and positioning them correctly.

Context

Recent Fisch guides and update coverage show the game is still getting active content changes, so mastery requirements can shift with newer patches and event systems.

TL;DR

All you really need is: run the Lullaby modes for 3 minutes, complete the starfall metronome step, catch the six required fish, then use them above the clouds to open the portal and finish the climb.