How much would it cost me to ship bettas from us or uk to singapore?And i heard about something called the oxygen stone which would last a month in the water.
I think you'd need to send them Global Priority which would take several days and would be very expensive. If you go into the postal site.... www.usps.gov you can calculate the cost based on the weight of the package.
I would like to say that it would be fairly easy to do this, but if I were you, I'd call around first. Singapore is quite the stickler when it comes to fish coming *in* to the country.