Verified answer

In the middle of october.

Pisces is visible right now in the evening sky (I was looking at it last night, in fact). About the only time it _isn't_ visible is when the Sun is actually in or near Pisces. In fact, since it's a large constellation, when the Sun is at one end of Pisces, the other end is in the dark, so is visible. So probably the _only_ time part of Pisces isn't visible is when the Sun is right in the middle of it, around March 30.

As someone else mentioned. Pisces is a rather insignificant constellation, with no bright stars, so it's hard to see unless you have very dark, light pollution free, skies, and know exactly where to look. It's located below (south) and to the left (east) of the Great Square of Pegasus, one of the most obvious asterisms in the autumn sky.

Keep in mind that the brightest star in the constellation Pisces is Eta Piscium and it is only magnitude 3.6. That means that the entire constellation is nearly invisible in significantly light polluted skies. If you live in or near a big city, I wouldn't count on seeing it from your front porch.