As everyone else here has said, be sure to do the research and soul searching to make sure this snake is really what you want. I have both a female green anaconda and a female yellow anaconda. The green is probably my favorite snake that I work with period, but she is also the most work. She is a 5 1/2 year old CB and has a great disposition, but at 14 feet & 150 lbs she is not easy to work and it can be a major fight to get out of her 150 gallon pond. Also, as to their strength, I also own and work with rock pythons and retic's and even though they are exceptionally powerful animals, the green anaconda makes even the 16 to 20 foot retic's seem like weaklings. The point I am making is that a female green anaconda is an animal that deserves all the respect that you can muster. I honestly do not know how you would ever work a really aggressive adult female green, so be sure you purchase a CB from a reputable breeder with excellent captive stock (i.e. good temperaments). As to their requirements, Kelly has raised his without a large water source and has had excellent results. So has NERD. I started out with a large water source and so I have moved up the size of the "pond" with the size of the snake. If you go this route the water must be heated to 80 to 82 degrees and must be kept very clean. I started out using a plastic kitty litter pan over a heat source (heat tape on the outside of the cage) set on a thermostat at 82 degrees. As she has grown I moved up to plastic cement mixing pans, pre fabed plastic yard pools and now, her last pond, a 150 gallon plastic stock tank, with an enclosed by PVC pipe, titanium heater that is attached to the pond via a 5 inch stainless steel bolt and wing nut (through the PVC housing). Her enclosure started out as a 4X2 melamine cage with plexi glass font and went on to a 6 foot vision (which now houses the yellow) to an 8 foot Neodesha (now houses a male rock), and finally a 6X8x7 walk in plastic reinforced shed (inside my reptile house). The doors are secured by locks on the inside on one door and 2 bolt locks and a door lock on the outside. Belly heat is offered on one side via heat cord under the fir bar substrate on a rheostat, and her lighting is on a timer that gives between 10 to 12 hours of daylight throughout the year. Her environmentals are as follows: humidity at between 55 to 70%, temps are 80 to 85 as background with a warm spot of 90 during the day and 78 to 80 at night, with the warm spot turned off, unless she has recently eaten. Her pond is maintained at 82 degrees. She is presently fed once every 8 weeks and is fed one rabbit between 9 and 11 lbs. Following her feeding her pond is pulled and replaced with a large ceramic water dish, as it is nearly impossible to maintain a clean pond for the first 14 days following her feeding as she urates daily in the pond if it is available. Interestingly she urates less when the pond is removed and the water dish is substituted. The only aggression she has shown is following the move into her new large enclosure this spring. She was also being dieted as she is a little "fluffy". After moving her in the night before I went out to check on her the following morning. Upon opening the door she exploded out of her pond with her mouth wide open. The only thing I saw was the white lining of her mouth. She struck for my face and she rose nearly six feet out her pond to do it. Luckily she missed, and I am still amazed that I can move as fast as I did. She gave no indication that she was going to attack, and I am damn glad that I entered her enclosure cautiously as she was all business that day. Needless to say I fed her the next day and haven't had a problem since, although I still exercise extreme caution with her (as I do around all large snakes, crocodilians, and venomous)especially around week 8 when feeding day is close. Anyway, if you go with a green anaconda, be sure you know what you are in for and be sure you are in it for the long haul and for the right reasons. Remember that they need large enclosures, with large ponds if you raise them in a naturalistic setting. Also, remember that they create large messes, are destructive (mine popped the wall of an $800.00 Neodesha like it was crate paper) and have the ability to kill you as adults. Keep all the large snake precautions at the top of your priority list i.e. smelling salts, alcohol, and hot water handy when handing them, make sure there are enough people in the room in case of an emergency, tap train them with a long pole for maintenance reasons, and never let down your guard. Also, remember that their metabolisms are slower then those of some of the other large snakes, with obesity being a very real problem with captives.
Good luck,
Shane