I got into fish keeping about 4 months ago and my dad got me a book on tropical fish, so naturaly i looked through the book to see what the bigest fish there was, and it was the red tail catfish, and said it grows to about 2m long (6' 6" ish). I then went to do quite a bit of resreach about them, not actually thinking you could buy them that easil, in the uk anyway. Most places said a 2000 gallon tank is the absolute min for one of these and i you would need a custom tank with a custom filter and heater and stuff. I tried to work out if a 2000 gallon tank would be enough and i wouldnt think it is, 2m is basicly the hight of a door, so a fish thats as long as your door would need a massive tank. I was also shocked and amazed to see my local pets at home selling one. I completely agree with invaderwithkey that fish that big should need a permit. Although if i did win the lottery i might be tempted to get one, but i guess with tanks that big i might as well open a public aquarium.