Two amazing bands with fresh visions of world music, especially with Gypsy and Balkan roots and ’20s jazz at the birth of swing, return for a night of wild revelry and dance: Fishtank Ensemble has just returned from a European tour and is now in a bicoastal visit to American clubs and concert halls, previewing songs from its soon-to-be-recorded fourth CD, due next year. It also includes crowd favorites from the past.

Fishtank Ensemble is the leader in high-energy, cross-pollinated Gypsy music, conjuring settings from the smoky cafes of Bucharest to the Gypsy caravans of yesterday. The band plays a unique blend of Transylvanian Gypsy anthems, Balkan, klezmer, and original music melded into group compositions that add flamenco guitar, French chanson, and Swedish and Japanese folk music, all rendered with a rare instrumental lineup. Fishtank Ensemble includes multitalented Gypsy violinist Fabrice Martinez; musical saw wizard, violinist, and singer Ursula Knudson; flamenco guitarist Douglas “El Douje” Smolens; and multigenre master Djordje Stijepovic on slap bass. Fishtank takes its name from the Oakland performance space where the bandmembers first met in 2005.

The San Francisco Chronicle calls the music of the Sour Mash Hug Band “an irresistible mix of old-time, Gypsy, bluegrass, jazz, Irish, and ragtime.” Known for its original tunes reminiscent of Kurt Weill and Danny Elfman, the eclectic, acoustic dance group also plays everything from Romanian couple dances to Appalachian hymns to klezmer to Harlem swing. Sour Mash Hug Band started in Eugene, Oregon, in 2005 as an old-time band with the classic lineup of clawhammer banjo, fiddle, guitar, and bass. After a year or two in Eugene they took to the road and for the past few years have split their time between San Francisco and New Orleans, with a few side trips to Romania and some touring in between. Fiddler Mickey Lee, the grandson of a Hungarian violinist, was brought up in the old-time Ozark tradition. Other bandmembers are accordion, trombone, and banjo-lele player Shiri Goldsmith; Blu Beverage on six-string banjo and tuba; and Aaron Goldsmith on upright bass, gitaron, and ukulele.