First of all change the setup. Get him on plain papertowels with a hidebox and a SMALL waterbowl that will not allow him to crawl inside and soak (bad for the wound...especially since they tend to defecate in their bowls). As well, keep the wound clean. Some people use peroxide(I believe) but I personally just use the plain neosporin. At the shelter where I work we wash all cuts with a weak cholorohexadine soultion (commercially known as Novalsan). I would just wait and get some neosporin tomorrow, but that is me. Keep him warm, mid80's or so in the basking spot (Warmest spot). The wound should heal up fine depending on what you call a good portion of the tail. Is it as far as the anal slit, or is it just most of the tip? Water snakes do, in fact, have the ability to shed their tails as the bones are weekly fused, much like a lizard, but the snakes will not regenerate their tails. If that is what happened, just keep the wound nice and dry/clean. Good luck. Andy
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Andy Maddox
Houston Herp Key
The Reptizone