Entirely different planets are ruling in nature in this combination. They are worlds apart and it will be difficult to find common grounds. Positive, active , Aries cannot fathom the nebulous, mysterious substance of Pisces who often irritates by appearing to be negative or indecisive.
Pisces-Aries Compatibility

Even if they end up hating the sight of each other, they'll still have a potently passionate peccadillo in the meantime. Pisceans love erotic, exotic fantasies and have a penchant for hatching up a playful plot or two. The arian's love a good game, so they could be just the ones to join in for a Pisces. n a close relationship, though, their different desires could clash.The fishy feeling for romance at every turn could conflict with the Arian aim of doing their own thing.

Aries (Mar 21-Apr 19) Taurus (April 20 - May 20) Gemini (May 21 - Jun 21)
Cancer(June 22 - July 22) Leo (July 23 - Aug 22) Virgo (Aug 23 - Sept 22)
Libra (Sep 23 - Oct 22) Scorpio (Oct 23 - Nov 21) Sagittarius(Nov 22-Dec 21)
Capricorn (Dec 22 - Jan 19) Aquarius (Jan 20 - Feb 18) Pisces (Feb 19 - Mar 20)

In general the above Generic compatibility analysis hold good for all zodiac signs. If you are looking for in-depth compatibility analysis or if you are a professional astrologer the below analysis of Zodiac signs Compatibility - between different gender of zodiac signs will give you detailed answer. Click the below link to learn more.

Pisces Man

Pisces Man Compatibility

Pisces Man and Aries Woman

Pisces Woman

Pisces Woman Compatibility

Pisces Woman and Aries Man