I watched this Least Grebe / Schwarzkopftaucher (Tachybaptus dominicus) catching fish in a small, artificial lagoon in Guatemala. Until this observation, I was under the impression that grebes (at least of the genera Tachybaptus and Podiceps) swallow food in whole. A quick glance into „Birds of the World“ and „Handbuch der Vögel Mitteleuropas“ confirmed that this is the current state of knowledge for Tachybaptus.
This bird however had a clear strategy of how to consume a prey item that was too large to swallow at once. Over a ca. 10 minutes long procedure, it squished and shook the fish, to break up the front part into at least nine smaller pieces. During the process, it lost the fish and dove after it repeatedly. See video below, filmed with Samsung S10e phone through Swarovski Optik ATX65 spotting scope. The first part breaks at 00:43.