Blue Dragon ask Glaucus Atlanticus is an beautiful sea creature I’m sure anyone would want one of them as a pet. Even they it looks pretty,Glaucus Atlanticus is technically a Sea slug Who wouldn’t want such a beautiful pet ? Unfortunately they are not exactly a something you can keep in your fish tank.
First problem is they feed on pelagic creatures, specifically on Physalia. Not exactly something you can buy from Local pet store or anywhere. Physalia is a jellyfish type of creature which can not keep in fish tanks. So even if you find one of these lovely Blue Dragons and provides a perfect environment it will starve to death. Here’s a video of one feeding on a Physalia,
Next problem is even more serious. This is an venomous creature. Glaucus Atlanticus can give you a very painful and potentially dangerous sting.
So sadly you can’t have them as pets. There are plenty of other nicer fish you can keep in a reef tanks including some types of sea slugs but not this one.