Answer by taking a quote from the following article:

Phish is an American rock band that was founded at the University of Vermont in Burlington, Vermont in 1983. It is known for musical improvisation, extended jams, blending of genres, and a dedicated fan base. The current line-up--guitarist and lead vocalist Trey Anastasio, bassist and vocalist Mike Gordon, drummer and vocalist Jon Fishman, and keyboardist and vocalist Page McConnell--performed together for 15 years before going on hiatus from October 7, 2000, to December 30, 2002. They resumed touring from December 31, 2002, until August 15, 2004, when they announced that the Coventry Festival would be their last show.

Phish was formed at the University of Vermont (UVM) in 1983 by guitarists Trey Anastasio and Jeff Holdsworth, bassist Mike Gordon, and drummer Jon Fishman. For their first gig, at Harris Millis Cafeteria at the University of Vermont on December 2, 1983, the band was billed as "Blackwood Convention". ("Blackwood convention" is a term from the card game contract bridge.) The band was joined by percussionist Marc Daubert in the fall of 1984, a time during which they promoted themselves as playing Grateful Dead songs. Daubert left the band early in 1985, and Page McConnell then joined the group on keyboards and made his debut on May 3, 1985, at a show at Wilks/Davis/Wing Dormitory on Redstone Campus at UVM. Holdsworth left the group after graduating in 1986, solidifying the band's lineup of "Trey, Page, Mike, and Fish"--the lineup to this day.  Following a prank at UVM with his friend and former bandmate Steve Pollak--also known as "The Dude of Life"--Anastasio decided to leave the college. With the encouragement of McConnell (who received $50 for each transferee), Anastasio and Fishman relocated in mid-1986 to Goddard College, a small school in the hills of Plainfield, Vermont. Phish distributed at least six different experimental self-titled cassettes during this era, including The White Tape. This first studio recording was circulated in two variations: the first, mixed in a dorm room as late as 1985, received a higher distribution than the second studio remix of the original four tracks, c. 1987. The older version was officially released under the title Phish in August 1998.  Jesse Jarnow's book Heads: A Biography of Psychedelic America details much of the band's early years at Goddard College, including their early relationship with fellow Goddard students Richard "Nancy" Wright and Jim Pollock. Pollock and Wright were musical collaborators, experimenting with multi-track cassette records to be broadcast on local radio. Phish adopted a number of Nancy's songs into their own set, including "Halley's Comet", "I Didn't Know", and "Dear Mrs. Reagan", the latter song being written by Nancy and Pollock. Jarnow argues that despite an eventual falling out between the members of Phish and Nancy, Nancy and his music were highly influential to Phish's early style and experimental sound. Pollock continued to collaborate with Phish over the years, designing some of their most iconic concert posters.  The band's actions demonstrate an identity with their "hometown" of Burlington, Vermont. By 1985, the group had encountered Burlington luthier Paul Languedoc, who would eventually design four guitars for Anastasio and two basses for Gordon. In October 1986, he began working as their sound engineer. Since then, Languedoc has built exclusively for the two, and his designs and traditional wood choices have given Phish a unique instrumental identity. Also during the late 1980s, Phish played regularly at Nectar's restaurant and bar in Burlington. In 1992 the album A Picture of Nectar, named as a tribute to the owner, featured a large orange with Nectar's photo superimposed subtly within the orange.  By late 1990, Phish's concerts were becoming more and more intricate, often making a consistent effort to involve the audience in the performance. In a special "secret language", the audience would react in a certain manner based on a particular musical cue from the band. For instance, if Anastasio "teased" a motif from The Simpsons theme song, the audience would yell, "D'oh!" in imitation of  Homer Simpson . In 1992, Phish introduced a collaboration between audience and band called the "Big Ball Jam" in which each band member would throw a large beach ball into the audience and play a note each time his ball was hit. In so doing, the audience was helping to create an original composition.  In an experiment known as "The Rotation Jam", each member would switch instruments with the musician on his left. On occasion, a performance of "You Enjoy Myself" involved Gordon and Anastasio performing synchronized maneuvers, jumping on mini-trampolines while simultaneously playing their instruments.  Phish, along with Bob Dylan, the Grateful Dead, and the Beatles, was one of the first bands to have a Usenet newsgroup, rec.music.phish, which launched in 1991. Aware of the band's growing popularity, Elektra Records signed them that year. The following year A Picture of Nectar was complete: their first major studio release, enjoying far more extensive production than either 1988's Junta or 1990's Lawn Boy. These albums were eventually re-released on Elektra, as well.  The first annual H.O.R.D.E. festival in 1992 provided Phish with their first national tour of major amphitheaters. The lineup, among others, included Phish, Blues Traveler, the Spin Doctors, and Widespread Panic. That summer, the band toured Europe with the Violent Femmes and later toured Europe and the U.S. with Carlos Santana.  Phish began headlining major amphitheaters in the summer of 1993. That year, the group released Rift packaged as a concept album and with heavy promotion from Elektra including artwork by David Welker. In 1994, the band released Hoist. To promote the album, the band made their only video for MTV, "Down with Disease", airing in June of that year. Foreshadowing their future tradition of festivals, Phish coupled camping with their summer tour finale at Sugarbush North in Warren, Vermont, in July 1994, that show eventually being released as Live Phish Volume 2. On Halloween of that year, the group promised to don a fan-selected "musical costume" by playing an entire album from another band. After an extensive mail-based poll, Phish performed the Beatles' White Album as the second of their three sets at the Glens Falls Civic Center in upstate New York. For their 1994 New Years Run, Phish played the Civic Centers in Philadelphia and Providence as well as sold-out shows at Madison Square Garden and Boston Garden, which were their debuts at each venue. Following the death of Grateful Dead frontman Jerry Garcia in the summer of 1995 and the appearance of "Down with Disease" on Beavis and Butt-Head, the band experienced a surge in the growth of their fan base and an increased awareness in popular culture.  In their tradition of playing a well-known album by another band for Halloween, Phish contracted a full horn section for their performance of The Who's Quadrophenia in 1995. Their first live album--A Live One--which was released during the summer of 1995, became Phish's first RIAA-certified gold album in November 1995.  Phish retreated to their Vermont recording studio and recorded hours and hours of improvisations, sometimes overlaying them on one another, and included some of the result on the second half of Billy Breathes, which they released in the fall of 1996. Alongside traditional rock-based crescendos, the album has more acoustic guitar than their previous records, and was regarded by the band and some fans as their crowning studio achievement. The album's first single, "Free", peaked at No. 24 on the Billboard Hot Modern Rock Tracks chart and No. 11 on the Mainstream Rock Tracks chart, becoming the band's most successful chart single of their career.

What was Rift?
That year, the group released Rift packaged as a concept album and with heavy promotion from Elektra including artwork by David Welker.