How Long Marinate Fish Ceviche?

How Long Marinate Fish Ceviche? After marinating for 10 to 15 minutes, the fish’s exterior will start to firm up, while the center will remain tender and moist—this is medium-rare. Let it sit for 15 to 25 minutes for medium, and 25 minutes for medium-well. Can ceviche marinate too long? Getting perfectly fresh fish (and