All Sphaerichthys vaillanti are NOT legal imports to Australia as of 20/10/2013:
http://www.environment.gov.au/biodiv...mport-list.pdf
however they may have been on previous import lists, have entered Australia prior to the implementation of import lists, or been misidentified on importation.

The IUCN Red List reports Sphaerichthys vaillanti as a species which is vulnerable with a decreasing population trend at 20/10/2013:
http://www.iucnredlist.org/search

It is very important not to release any aquarium specimens into our waterways. Any that are not sold or re-homed/ given away, can often be re-sold to aquarium stores. If they are homed in ponds, care should be taken that they cannot escape in run-off into our waterways. Even if fish are native & local they should not be moved from one waterway to another, as this can transfer disease. If they are not local fish, they can both spread disease and either out-compete or eat local fish, shrimp & plants, causing their demise.

It is a good fish for experienced hobbyists.