I put my boxer crab in my 10 gal nano tank, so I would think a 20 gallon would be suitable. They stay quite small.
I'm not sure how long I've had him 3 months now. He does stay hidden alot.
he molted once at least, I found his whole exo-skeleton.... thought it was him dead!
But spotted him again a couple of weeks later..... alive and well! :cheer:
Still waves those pom poms around . I tend to spot him in the evening when I turn the bright lights off and only the acenitc (sp?) lights are on.... he has his own little cave he has claimed.
Here's a pic when I first got him.
![](https://forums.saltwaterfish.com/image/noimage/true/width/525/height/525/flags/LL)