1. Size (tank + fish)
a good starter tank would be a small tank for one in the 2-4" range, but you will want to have at least a 180 gal set up and ready for it after a few months. Growth rate is around 2-4" a month until it hits the 12-16" range. It should hit 16"-24" in the first year. Mine is currently 38" and around 4 years old. The 180 gal would only last maybe 1-2 years max, and you would need a tank of 8' x 4' x 2.5' minimum for life, but 10' x 5' x 3' would be ideal. Tropical ponds are a great cheap alternative!
2.Price of fish
Depends on where you are at, how big the fish is, ect. I've seen them as low as $25 for 3", and as much as $75 for 4"
3.Where to buy them (LFS or ONLINE)
Check out the buy and sell section of this site.
4.Temperature
I've found that they do best from 75-85 degrees, and feed more and more the higher the temp. I've had a heater failure and the water was down to 45 degrees F. He pulled through, but I wouldn't suggest it.
5.Ph
Neutral works best
6.Aggression (1-10)
It's not really a matter of aggression. They are not very aggressive except to other catfish I've found, but they need plenty of room as they will establish a territory, and defend it when in a smaller tank. Anything less than 3/4ths of their total size can be considered a meal. They have a huge head and mouth and will eat smaller fish, or animals.
7.How much food do they eat (1-10 HIGHEST)
At 3'+ mine eats on average about 4 lbs of shrimp, pellets, and fruits weekly. He eats from my hand and has from day one. He will come to where I am to be petted even after completely full. If I let him he will eat up to 4 lbs of shrimp in one sitting. I've fed him 2 lb market tilapia whole before(not recommended), I was bored and just wanted to see what he could do. I tried to temporarily house a 14" oscar with him to see it hanging out of his mouth, and it was completely gone a day later.
8.Do you have pictures
I do.
9. Can they breed
No, they are a sterile hybrid.
10.Does this fish have a personality of its own
As said before they can be petted, hand fed, and are sometimes picky. They know the hand that feeds them, and if you bring someone unfamiliar in with you to feed mine he shys away and won't eat. Take them away and he'll eat right away. I think mine becomes more picky with age. I fully expect he'll reach more than 4' eventually.
Hope some of this helps! Also just remember that these pics are of my fish after he fasted for about 3 months which I find he does every winter since he's kept in a mostly unheated garage. Although his water is always above 70 he does not eat when it's cold outside. He's been eating again for about a month now and has added about 5 lbs of bulk back on. They get very thick when eating on a constant basis.
) but all the information there is what you need to know.