Tl;dr
Mercury in Pices:
Your ideas and thought processes do not come to you in an orderly, logical fashion. Instead, you think with your feelings or with images produced by your rich and fertile imagination. A very subjective person, your dreams and fantasies are very important to you. You trust your intuitions and tend to reject ideas that are based solely on logic. Very impressionable, you are sensitive to the moods and emotional states of those with whom you come into contact.
Mercury in Pisces are gentle communicators with a soft touch that is pleasing and warm. Some of them come across in an almost poetic way. Not given to bother too much with details, these individuals tend to sponge up the feelings and moods of their environment. The information they extract from their surroundings can be unusual and certainly unique. For some, it is heavily skewed in the direction of emotion and feeling.
They're generally lovely listeners and, when you get them talking, warm conversationalists. When it comes to communicating, they're moody, and this extends to their letters and emails too. It's a kind of odd thing - you never know when they'll be in a quiet mood or a yakking state. These individuals don't compete for air time, but they can talk up a storm when they're in the right frame of mind. Predicting when that will be can be difficult, though. Mercury in Pisces is tactful because they don't want to offend others in any way. They feel out their audience and sometimes search for what they think others want to hear. Yes, Mercury in Pisces can fib. It's not that they are malicious-they simply want others to be comfortable.
These people come across as dreamy and indirect. It can be hard to pin them down to any one belief or decision. It's not that they want to drive you crazy or anything-it's just that Mercury in Pisces takes in so much information from the world and their open-mindedness prevents them from taking a stance for too long. They have an unusual aversion to cold facts and hard decisions. Driven more by intuition than facts, these people avoid list-making and the like. Others might think them disorganized but they have an uncanny knack of finding things nonetheless. There is a tendency to avoid detail work or tying up loose ends, not to mention the mind drifting off to Never-Never Land.
Mercury in Pisces is tuned in to all the nuances of subjects and environments. They pick up on subtleties of all kinds, so what they lack in organization they make up for with insight. When the Sun Sign is Aries, much of the brashness and directness of Aries is considerably toned down with Mercury in Pisces. Aquarius Sun people with this position are artistic and humane.
Mercury in Pisces people are often vague and indirect in their communications with others. If they learn to express themselves with more clarity, they'll find that a lot of the problems they can encounter with misunderstandings will lessen. Their impressionable nature can make them an easy target at times. Their plans may seem too dreamy and unrealistic to more practical sorts, lacking the details that make them seem more attainable. But Mercury in Pisces' vision is extraordinary, and their leaps of faith are admirable.
Favorite expression: "I believe..."
Venus in Pisces: Hmm...don't like this one as much...
Venus in Pisces people project themselves as dreamy, soft-hearted partners. Everything about the way they flirt promises a lovely time. Theirs is an elusive charm - they are sweetly playful, a little moody, and perhaps a little irregular. They appreciate romance and poetry, and they prefer to "feel out" both you and the relationship you share, so don't expect too much planning ahead. Their sensitivity can be a little misleading at times. Yes, they are sensitive folk, but lovers may find it maddening that this sensitivity is not only directed at them, but towards all of mankind.
Venus in Pisces men and women want you to know that their love is unconditional. They are unimpressed by your status, and love and accept you for all that you are inside. They love the underdog and are attracted to wayward folks, or those in need of a little help. With their romantic view of the world, they can be unreasonably attracted to states of suffering and martyrdom, so they easily get into the role of saving someone, or being saved. Unlike Venus in Libra, which thrives on equality, Venus in Pisces is actually turned on by inequality! They can be rather confusing and hard to pin down as they feel their way through their relationships. As much as they may want to, they find it hard to commit. Many do end up committing, however, at least on the surface.
Pleasing Venus in Pisces involves enjoying tender moments and romantic times with them. You won't always be able to count on them. In fact, you can be sure they will stretch the truth every once in a while. But remember they do this because they fear they might hurt you, and they can't bear to cause you any heartache. Try to understand them, although that's never an easy task considering the fact that they don't always know themselves. And, truth is, some Venus in Pisces privately have a love affair going with the idea of being misunderstood. Try to put up with their apparent lack of direction in the relationship - they are so receptive and open to all possibilities that it is hard for them to commit to any one thing, idea, or even person. These intriguing partners will reward you with a love that is accepting and comes as close to unconditional as humans can get.
Here's the other one, which I like a bit more:
You have a dreamy, fanciful, romantic nature and a very creative imagination. Indeed, at times, your private fantasies are more appealing than the reality around you and it is difficult for you to leave them. You tend to be unselfish and giving in relationships and are extremely sensitive of the needs of others. Be very sure that those you help are worthy of your devotion and are not merely taking advantage of your innocence and naivete.
Mars in Pisces:
Mild-tempered and gentle, these guys and gals move through life in a manner that can hardly be considered direct. Mars is the planet of action and assertion, and Pisces is a passive sign that rarely asserts itself in a direct fashion. So the placement of Mars in Pisces is an unusual combination. Sometimes prone to feelings of guilt about their anger, and difficulties with asserting themselves, Mars in Pisces individuals seem to "go with the flow". This is certainly not a very active position for Mars, and natives will often let life "happen" instead of trying to control their life direction. This is a charming position, as individuals with Mars in Pisces don't appear like they are capable of harming a fly. However, those that don't find creative expression for this energy can stir up a storm through indirect aggression.
Mars in Pisces people are not averse to playing games to get what they want, although even they don't always know exactly what they do want! Their desires are changeable and moody, and it's hard to really know where these natives stand on any particular issue. Alternatively, some Mars in Pisces people do take a stand on issues that are Piscean in nature, making compassion and love their mission.
Energy levels fluctuate a lot, coming in bursts of activity followed by inertia. Because it can be difficult to align this ebbing and flowing of energy in the day-to-day world as it is, finding a job that supports this may be tough. The happiest Mars in Pisces individuals are those that have a creative outlet that allow them to express their desires of the moment, their compassion- and even their anger- freely and imaginatively. An example of Mars in Pisces is Bono, lead singer of U2, who seems to have found the perfect outlet for his creativity through his music, and as a spokesperson for love and compassion.