St. Petersburg police said Gary Williams, 53, took out a cigar just before 1 a.m. Friday and his brother, Dean, 53, threatened to set the residence on fire if he did not listen, The St. Petersburg Times reported Wednesday.
Investigators said Gary Williams then stabbed his brother once in the shoulder with a "sharp instrument."
Dean Williams, who said he did not see the object with which he was stabbed, called 911 from a neighboring apartment where another brother lives.
Police said they believe alcohol was involved in the incident.
Gary Williams was arrested and held without bail.