Well i thought about all the pros and cons of keeping him and here they are-
Getting to look at an awesome invertarbrate.
Feeding would be amazing
Setting up another tank
And the cons-
The chance of it getting provoked and breaking the glass
Breaking through the divider while in the 20 and then killing everything
The work in setting up a new tank
The special food need for feeding
Risking getting a finger or two broken
So after thinking about it for 2 days i decided not to keep him, i traded him to the lfs
for a piece of rock as i couldnt get him out of him former rock. They acclimated him and he is in the fuge of one of the 40b they have. Thanks for all the help!