The requested vessel with name BLACKFISH and MMSI:503000120 and IMO:0 is temporary not in our database.
Perhaps you mean one of the following ships:

Vessel name IMO MMSI In range Destination Last report
BLACKFISH N/A 219019409 Dec 10, 2017 08:18 UTC
BLACKFISH N/A 235073568 Nov 12, 2017 10:21 UTC
BLACKFISH N/A 367786430 Sep 14, 2017 20:35 UTC

Also, you may try to find the vessel in our comprehensive Vessels Database or track this ship on the map.