Make sure he is properly hydrated! I just went through dealing with two imported snakes (a very young tiger rat snake and an eastern tiger snake). I very nearly lost both of them due to severe dehydration. Both showed symptoms of being extremely listless, not tongue-flicking, very little eye movement and overall just limp. The symptoms came on pretty suddenly too and both incidents happened several weeks apart, but were almost identical in their presentation. I honestly thought I was going to lose both animals. With some heavy misting right on the head though, both animals drank copious amounts of water twice daily for several days. I also soaked them for about ten minutes at a time for a few days as well. Both have now snapped back 100%. I think some fresh imports, especially semi-arboreal types, arrive dehydrated and then just take some time to figure out water bowls. Good luck with your mangrove.
Billy
>>I just received a mangrove snake from Indonesia and he appears to be doing outwardly well. He's about 3.5 feet long and barely a scar on him, which is good considering he is WC. However, when his daytime light cycle is on he buries himself under the substrate and seems completely unresponsive to my pokes and prods. I know they are primarily nocturnal but the fact that he rarely even flicks his tongue or moves when i attempt to move him is a little odd I think. He also was puffing/wheezing a bit when he was breathing so I raised his temps to about 90* and humidity to 80% to prevent the onset of any possible RI. Anyone with Mangrove experience let me know what you think.