In Israel this is not really even allowed. The plan was going to be to get the alligators (crocs?) from the Chamat Gader resort and relocate them to the Ketziot prison in Southern Israel. The National Parks and Nature Authority said they will not relocate the gators as the gators can only be used in Israel for research and education. To cricumvent that Silman signed an order changing the classification of the alligators (crocodiles?) to something like "managed wild animals for security needs" so the Nature Authority's objection would be moot and they could then be put in the moat. 

Is it feasible or not? Plenty of discussion on the Internet about that. Maybe it is too expensive as the gators need to be cared for and fed, given medical care and whatever else gators require? Maybe they are not even effective at stopping prison breaks - gators sleep a lot and don't need to eat much (but no, I would not want to swim across a moat populated with possibly hungry gators). I don't know the answers to the big debates about this, but I do have one question I have not seen discussed at all.....

How common is it for terrorists or other "security prisoners" to escape from prisons in Israel that an alligator moat might even be effective and worthwhile? How common are prison escapes in general, even by regular criminals and not terrorists?

How necessary is it really, and if it gets done will it even accomplish anything that is not already being accomplished by normal security measures? Is there truly any purpose of it for anything more than some "likes" on social media, and some articles in the press that will excite some people before elections?

sources: i24 News, Ynet, Hatzinor