Another Thai greeting is the "wai," consisting of palms pressed together with the hands held against the body. The higher you hold your hands the more polite your wai. Bela doesn't do that here not only because he does not have hands and can't touch his pectoral fins together but because it is a faux pas to wai to service people like the security personnel at an airport. They might wai to you but you do not wai back.
The greeting that Bela offers here is also sometimes transliterated as "sawasdee krab," which is probably more appropriate for use by Thai fish and other aquatic creatures.
Fortunately I did not really try to take Bela on the plane this past weekend when I went to Kansas City for a cousin's wedding. I don't know what would happen to a tiny fish on an airplane, even if I were allowed to take him on board. The changes in cabin pressure might harm him.