A thing to remember here is that these posts are strictly meant for the particular planet position. Like, today we are looking at Rahu in Pisces, so the description given here may change for you if your Rahu is although in the sign of Pisces but with conjunction with or aspected by other planets. --
Rahu represents illusion, foreign lands, foreign things (foreign as in unknown things. So, for someone living in Punjab, culture and rituals of Kerala is also unknown and hence Foreign), Drugs, Medicines, any type of intoxication, fame, wealth, success, obsession, past-life left-over karma, movies, television, online world, cheating, imagined fears, unusual things, unique things, creativity, rule breaker. Rahu also blows things out of proportions.
As Pisces is the 12th sign of zodiac belt, it represents the same energy and things which are represented by 12th house such as Isolated Places, Spirituality, Imagination, Other Dimension or Other World etc. Besides these things, it also represents your Hidden Talents, Ability to work in background, Spiritual Self etc. Pisces is consisted of last 2 and half nakshatra, i.e. Purva-Bhadrapada, Uttara-Bhadrapada & Revati. Pisces' lord is Jupiter.
One thing we have to remember with posts related with Rahu through Signs is that Rahu converts himself as the lord of the sign it is sitting in and then amplifies quality of lord. Like, when Rahu is in Pisces, Rahu will take all the qualities of Jupiter (Lord of Pisces) and then will amplify those qualities out of limit. Rahu also does same to the planet it is sitting with. Like, if Rahu is with Saturn then it will take all the qualities of Saturn and blow them out of proportion during Rahu MD or Saturn MD. It is always better to have Rahu alone in a house rather than conjunct with a planet. Another thing with Rahu is that recently I have come across of the view that Rahu and Ketu don't have aspects on 5th or 9th house, for the simple reason that they are shadow planets and for aspects you need a sight not shadow. I am yet to verify it on at least 50 charts, so for now I will continue with traditional approach of 5th and 9th aspects of Rahu. Ideal placement for Rahu is to sit with an exalted planet, then it takes all the qualities of the exalted planet and amplifies them.
So, finally Rahu's journey ends in the sign of Pisces and this is the only place where this negative energy becomes kind of positive. Here also Rahu becomes obsessed but as Pisces is sign of Spirituality, these people become obsessed for spirituality, imagination and creativity. These people can become extra-creative as Pisces is also sign of imagination and other dimensions. They become voracious readers too. They keep a very weird or unusual approach to God and Spirituality and end-up in spreading that approach to the world. They can be easily seen as a person who is travelling to many places to preach on God and Spirituality. It won't be a surprise if they end up in creating their own religion. One example on top of my head is Osho Rajneesh. These people should always involve themselves with the work related with Spirituality or Creativity. A 9 to 5 job in a corporate is not meant for them. Even-if they keep themselves in job set-up, not only they won't feel happy there but situations will always lead them to be in spirituality related work. Omens are powerful medium to understand God's will, But this is the best position of Rahu among all 12 signs and needless to say that in that spiritual work also Rahu is able to satisfy its material desires. Not to forget that Osho Rajneesh was able to live the most luxurious life of all times. There are two ways to look at the results of all these acts. Some people say that all these acts are paying them money in the end, hence they are doing it. I feel that money is the most natural outcome of any work. You do any work in this world and you will get money. There is no work in the world which doesn't pay you back. So, I feel that the basic fact that they are dedicating themselves to a higher cause is meaningful and most important. Money is an outcome which is bound to come.
As always, Rahu's placement in different nakshatra will change this scenario as per the position of Nakshatra Lord. If Rahu is in Purva-Bhadrapada Nakshatra, then Jupiter will have its impact on Rahu. If Rahu is in Uttara-Bhadrapada Nakshatra, then Rahu is impacted by Saturn. Likewise, if Rahu is in last nakshatra of Revati, then its lord Mercury's position would impact Rahu.
Sign lord wise, Jupiter is lord of Pisces. So,Jupiter's position will have highest say on how Rahu works in Pisces.