I've got an idea...Do you know those drink containers that have multiple slots for drinks? Izze has them...some sodas do such as Jones or old Coca Cola bottles. Basically any drink that comes in 4-pack bottle or so.
Anyway, the drink boxes have great slots that are perfectly shaped for a cup. So, if you still have the cup from the pet store (or cover any other shorter-ish tumbler--you can cover the top with mesh and a rubber band) you can put your bettas in two separate cups in two of the drink slots.
Then you can find a basket or something of a larger size to then put the drink box inside of. Finally, put a scarf or towel or blanket or something soft in the gaps between the edges of the basket or box and your juice box inside. Just keep adding soft things until the juice box doesn't move too much when you wiggle it.This will keep the fish from getting jostled too much. If you happen to use a basket, you can even loop the seat belt through the handle!
PM me and I can send a JPEG of the carrier idea. I didn't really want to put it on the public forums because I had the image in a a booklet for college, and I'd like to keep the rights to it :).
Last edited by kitkatbar; 12-24-2011 at 04:59 PM.