Start the dash as close to the door transition as possible in order to store the shinespark in time. Stand 2 or 3 pixels from the door for run speed to be low enough going into the next room. Spark up and fall onto the platform left of the fish.

Entrance condition:

"comeInRunning": {
  "speedBooster": "yes",
  "minTiles": 0.4375
}

Requires:

"canWaterShineCharge",
"canShinechargeMovement",
"canDodgeWhileShooting",
"canTrickyJump",
"h_shinechargeMaxRunway",
{"or": [
  {"shinespark": {"frames": 43, "excessFrames": 9}},
  {"and": [
    "canMidairShinespark",
    {"shinespark": {"frames": 38, "excessFrames": 9}}
  ]}
]}