Jupiter is considered to be the most benevolent planet in Vedic astrology. It represents prosperity, wisdom, knowledge, and expansion. However, when Jupiter is placed in the 3rd house for Aquarius lagna, it loses its strength as it is in an enemy sign state. This placement also has a direct influence on the houses that Jupiter rules.
In this position, Jupiter becomes the lord of the 2nd and 11th houses. The 2nd house is related to finances, speech, and family while the 11th house governs gains and income from various sources including friends and social networks. Jupiter's placement in the 3rd house may cause some delay or obstacles related to finances but eventually it will help in accumulation of wealth through proper use of communication skills.
Additionally, since Jupiter is also natural karaka (significator) of the 5th house which is associated with progeny, education & new ventures and the 9th house which stands for higher education, luck & dharma (righteousness), one can expect a positive influence of Jupiter's aspect on these houses.
On the downside however there may be some challenges pertaining to relationships due to Jupiter's negative aspect on the seventh house (partnerships & spouse). It may create some tension causing stress or delays regarding marriage or other partnerships.
Jupiter's beneficial influence on the ninth house (higher learning), offers great opportunities for success in academic pursuits provided necessary hard work combined with moral ethics is maintained. It might lead to establishment abroad or earn accolades through international recognition as well.
Furthermore considering that Jupiter aspects its own karaka houses - second(family & speech), fifth(childern & creativity) and ninth(higher studies), this gives a wonderful opportunity towards growth,making progress intellectually as well as financially
To sum up, placement of Jupiter in third house for aquarius lagna can bring about challenging circumstances initially because of its state of enemy sign, but when combined with the influence on its ruled houses - 2nd and 11th house it can create great opportunities for financial stability through effective communication.
Besides, Jupiter's placement in third house also suggests that though there may be slight delay one can expect prosperity especially in terms of progeny (fifth house), overall growth through higher studies, and recognition beyond home land(ninth house).
It is important to remember that astrology should not be blindly used for making decisions; as every individual's horoscope is unique. It is always recommended to consult an experienced Vedic astrologer to understand how this placement would affect each person as a result of their birth chart analysis.