Not many clues to follow-up on with the information given. Most tank deaths result from poor water conditions, such as an ammonia spike, or aggressive tankmates, temp. extremes, lack of oxygen, or death for no apparent reason.
The other tankmates probably nibbled on the deceased fish. They usually eat the eyes first.
Just keep an eye on the other fish and your water parameters. Might be a good idea to do a 25% - 35% WC. Note: I found one of my 6 y.o. Silver Dollar fish dead just the other day, no apparent cause. It happens to every one. Good luck.