Usually the breeder will tell you the next shipment dates and list the transhippers recieving fish and you choose from that list. For example when I imported my super red pair Linda and Julie were the only ones listed. Also every bettas bag contains your name, adress, and email...so I think the transhipper actually contacts you.
Who am I? Well I am a Junior Member of the International Betta Congress and a breeder of white HMPKs, red dragon HMPKs, black/red dragon HMPKs, metallic multi HMPKs, blue masked HMPKs, and now multi color HMs. Soon to add black HMs. I will be showing in New Breeder class in fall of 2012.