Copyright 1991 The Chronicle Publishing Co. The San Francisco Chronicle FEBRUARY 27, 1991, WEDNESDAY, FINAL EDITION SECTION: DAILY DATEBOOK; Pg. E4 LENGTH: 505 words HEADLINE: Jellyfish Treads Water at Slim's BYLINE: Joel Selvin, Chronicle Staff Critic BODY: With a supple, polished debut album that earned the band a small fortune in a record company bidding war and a video in heavy rotation on MTV, Jellyfish is poised to sting. Rising out of the remnants of Beatnik Beatch, a South-of-Market club band that managed to get an album released on a major label a few years ago, the Angloid pop-rock quartet drew a full house Monday at Slim's, a clear sign of a genuine following in deve lopment. Alas, the gig was not impressive, and the band came off as a shallow, contrived set of studio-bound popsters who put more energy into costumes and set design than into performing. Not that there weren't extenuating circumstances. Regular guitarist Jason Falkner was missing in action, although substitute Niko Wenner filled in admirably. Vocalist Andy Sturmer complained of voice problems, almost like offering an excuse before he put on a lousy show. DEEP-ROOTED PROBLEMS But the problems with the band ran deeper than an ailing guitarist or a singer with the ague. Opening to strains of the old Argent hit, ''Hold Your Head Up,'' the quartet appeared on a stage outlined by Christmas lights strung along fence posts, ivy twined around the mike stands, flower pots on the amplifiers and a bubble machine in the backgroun d. The four musicians -- even the substitute -- wore Day-Glo Carnaby Street campy costumes that evoked the psychedelic era of ''Sgt. Pepper.'' With Sturmer positioned behind a stand-up drum kit of three pieces and some cymbals, the band lined up like ducks in a row facing the audience. Sturmer remained anchored to his minimalist drum setup and none of the other musicians provided much animation . The show had a static quality that did little to enliven the music. Not only did percussion duties tie up the band's lead vocalist, the three-note drumming grew monotonous and hardly provided the rich percussive coloration the lush pop melodies require. CHIRPY CHEERFULNESS The Beatles may be the obvious reference point to the Jellyfish sound, although the chirpy cheerfulness of the Turtles and the Monkees might be more to the point. Actually, the band paid tribute to Beatles imitators everywhere with back-to-back covers fr om the songbooks of Wings and Badfinger. The band returned for an encore with a faithful rendition of Fleetwood Mac's ''Go Your Own Way,'' which may have been what passes for Jellyfish's sense of humor. The original material floats on sturdy melodies, decorated with soaring harmony vocals and billowing keyboard textures. ''All I Want Is Everything'' contained some gritty rock drive, while ''I Wanna Stay Home'' created a near-wistful mood with its breath y air. The strength of the band's songs and the striking, if somewhat manufactured, look mark Jellyfish as a band with serious commercial potential. Everybody has off nights and the group will undoubtedly live to laugh at the relative debacle of their big homet own nightclub debut. Fans of the band's appealing album couldn't help but have been disappointed. GRAPHIC: PHOTO,Andy Sturmer, vocalist and drummer for Jellyfish, wore Carnaby Street garb for the band's date at Slim's , BY JOHN O'HARA, THE CHRONICLE