I know a number of hobbyists that have their mandarins eating NLS, some for years now. NLS is also one of the main foods fed to the captive bred fish at the ORA facility.
http://www.orafarm.com/products/fish/dragonets.html
The fact that a pellet has a high moisture content, and is soft, has absolutely nothing to do with digestibility, or overall nutrient content.
Well done on the mandarin, Ken.