It only cost $5 for the breeders overseas to ship to Linda...your biggest expense is the overnight shipment from her. If it only costs them $5 to ship them over (I'm sure they ship numerous over at a time though) I don't see that they care about the fish coming over here all that much.
If you were to put them in desani bottles and have them in your carry-on bag..honestly I don't think they'd care. So long as you aren't carrying weapon's lol they don't look too closely at anything else.
Although, I've never travelled overseas
...maybe you could call the airport customs department and ask them about it, I'm sure they'd be able to tell you what you need to do.