Hey guys I just joined this site to learn a little more about aquaponics and Tilapia.I know this threads old but I ran across it and figured I might jump right in and try to offer my piece.I have very extensive knowledge of Hydro/Aeroponics but even more about Catfish.I grew up on a farm in Tennessee and caught and ate catfish around two to three times a week so by the time we were in highschool several of my hunting buddies and myself had our own little cow pond where we bred and ate what we all still believe to be the best fish any of us have ever eaten(2 marines,a doctor who lives in Japan,a professional angler,a fly fishing guide who lives in Idaho and,myself a luthier and banjo player that lives on that same farm in Tennessee).I would like to offer any and all knowledge I may have on them to anyone still seeking info. just message me and Ill try to help since I came to this site for everyone heres help yall can use me for any knowledge I can offer.To answer the couple questions I noticed here.Catfish do not really have a life expectancy since humans are their only real predator.Catfish have no real "adult size" they essentially will grow until something kills them.I have eaten a catfish I know for a fact was over twenty years old and have heard of them coming from our part of the Mississippi as much as 80 years old.This may sound absurd to people who arent used to catfish but we typically call a "game" sized cat anything that takes two people to carry.A local here caught the record a few years back(this is inside city limits in the middle of downtown Memphis) in the river at just over 180 lbs it was the largest catfish I have ever seen in real life.Finally,catfish generally will not eat another fish for food unless its already wounded or hes real hungry.However,Channel cats are very aggressive and will eat another fish if it "steps on his toes".Blue cat I have found to be the most gentle and have never heard of them being territorial or aggressive to others in their habitat.That being said,I have a buddy who runs a hatchery and says everytime he introduces an adult cat to any tank it usually eats a fish or two just to get the word out that hes not to messed with...I know this is an old thread but it popped up in my search and when i came here I saw unanswered questions so I answered thinking the guy behind me may well get the answers he was looking for when he was directed here...To answer the initial just order them from any of the farms around here (Google or Craigslist) and theyre usually a buck or two a piece plus sixty five for shipping