Chad Johnson -- Fired ... Again

Here's a shocker -- something actually lasted LESS TIME than Chad Johnson's marriage to Evelyn Lozada -- his endorsement deal with Zico coconut water ... because the drink company just fired his ass ... less than a month after signing him.

A rep for Zico released a statement today, saying, "In light of recent events involving Mr. Johnson, we have decided to terminate our relationship" with him. The "recent events" obviously refer to Johnson's domestic violence arrest this weekend ... after he allegedly headbutted Lozada.

The rep adds, "The values we espouse, through our employees, our customers and our brand, are central to our mission. We have taken this proactive step to demonstrate just how important those values are."

Zico signed Johnson on July 25th. Johnson married his soon-to-be ex-wife Evelyn on July 4th.