Okay, not really spiky, but it certainly looks that way. This, I believe, is a red lionfish. Not all lionfish are the same, and this guy was quite large. They have become an invasive species with very few predators to drive them off in the invaded regions. The promotion of consuming them has become very popular, but this guy seems to have avoided it for some time since he was pretty large. They can live up to ten years and their poison, although not deadly, can inflict severe pain, vomiting, and difficulty breathing.
This particular lionfish was found in Beqa Lagoon in Fiji, right off the coast of Pacific Harbour, about 40 minutes west of Suva. One of my favorite dives to date, where I got to feed sharks, explore a wreck, dive through some swim throughs, and explore healthy, habitable reefs. Truly an amazing experience! 2012-2013.