Bring back your bowl of zest now and put the halibut, scallops and shrimp into it.
 

 Step 6:

Then, add the remainder of your ingredients including the lime juice, ensuring you have enough juice to cover everything up.

Give it a good stir, and cover with plastic wrap and refrigerate for 18-24 hours, but remember to stir up the mixture every few hours if you can remember to.
 

 Step 7:

The next day, your ceviche will be ready. Strain what you want to serve from the lime juice mixture and rinse it so that it won't taste overpoweringly limey and serve.