Our Torah teachers tell us that this is the parting blessing that Yaakov gave to his son Yosef haTzaddik and his two grandsons, Ephraim and Menashe. It is Yaakov's intent that his particular choice of words work to strengthen his offspring so they will never stray from the path of Torah. How can a blessing that they increase and grow "like fish in the land" assure that Yaakov's offspring will remain close to Torah? For the answer, lets take a look at the nature of fish.
Have you ever noticed that when rain falls over a body of water, such as a lake, fish swim to the surface and open their mouths to drink in the splashing droplets? Fish live surrounded by and filled with water, yet they instinctively want more. The Midrash says this is an analogy for the Jew who lives his life immersed in learning Torah. When he hears a new Torah thought, he drinks in the fresh insight as if to satiate an unquenchable thirst.
Refreshing Our Lives as Torah Jews
We all want to enhance our lives as Torah Jews, yet total 
immersion in Torah learning is unattainable for most of us. One way we can imbibe holiness is to host a Torah scholar for a meal. The Talmud relates that when one hosts a Torah scholar in his home, it is as if he have made an offering in the Temple. This is because a pious person eats entirely for the sake of Heaven. Therefore, the food provided for him has the properties of a sacrifice in the Bais HaMikdash. The sanctity inherent in a tzaddik’s act of eating brings the Divine Presence to the table, and all present benefit.
Maybe you do not have the opportunity to invite a tzaddik for a meal. Nevertheless, every one of us can invite the Divine Presence into our homes.
Their First Torah Teachers
Showing respect for our tzaddikim: our Rabbis and Torah teachers, the Torah leaders of our community and the Gedolim of our generation, attaches us to the Jew who lives his life immersed in learning Torah. This is how we too can spiral upward towards the surface and be continuously satiated with the fresh taste of Torah.
We are the very first “tzaddikim” our children and grandchildren see, their first experience with Torah teachers. They drink in our every word and absorb our unspoken attitudes. Showing our interest in their lives, respect for one another and love of Torah and mitzvos are like sacrifices on the alter of the Bais HaMikdash.
We owe our lives as Torah Jews today to the blessing of Yosef, Ephraim and Menashe. And every meal is an opportunity to build upon this legacy. A simple meal of kosher food accompanied by a bracha and seasoned with a word of Torah is all it takes to bring the Divine Presence to our table. The ripples which emanate from such homes assure that the blessing upon Yosef haTzaddik and his children endures.
Develop and nurture a relationship with a tzaddik, find a Rav. Every Jew needs a Rabbi, to guide us, to help us achieve our goals, and, like our father Yaakov, to give us blessing.
Torah teachers are very accessible in the online world. However, finding the right Rabbi for oneself can be difficult. Rabbi Dov Roth devotes the better part of a chapter of his book Relevance: Pirkei Avos for 21st Century
to helping you understand the role of a rav and guiding the reader in developing that all important relationship. I think this book is an excellent resource.
