yes you can but i would only keep them in an acrylic it used to be a nuisance predator but now more and more people are realizing how cool these creatures are i am setting up a 60 long acrylic for the species that i showed the pic of heres a good web sight to get more info on them http://www.ucmp.berkeley.edu/arthro.../eumalacostraca/royslist/index.html#directory
The blue puffer if extreamly rare. I have only seen one in all the yeat's ive been keeping sw (about 12 years) I have not been able to even find any info on the net. There is a store in NJ that is quite pricy and they get in about 1 every 2 year's.
Sydney aquarium has a yellow port Jackson shark name Mango. He is about one in a million. Heterodontus quoyi may not be rare, but I am trying to buy one, and have yat to find a source.
that is one very nice puffer i love the color congrats mantis shrimps are awsome there is another member on here who has some very beautiful ones here is the link