There is a maximum limit, but the entry field will cut you off if you try to exceed it so that's not the issue here. I have renamed all my pets and had no problems with the names sticking. I wonder if the problem has something to do with the katakana -- it may be set up largely to accommodate latin characters. I'm just guessing here. You might want to try naming an animal with latin characters to see if you have the same problems. You could also email
support@teamlava.com since this might actually be a bug they would want to fix to accommodate international players