Bettas - Which sex? Which tank mates?

Question
Girlfriend just got a dark blue Betta and is keeping it in a gallon bowl with some round smooth pebbles on the bottom. I've told her the water needs to be warmer (I'll fix that)

I'd like to add a 2nd fish - like another Betta - but don't know how to tell which sex we have. I understand a Male/Female pair will cohabit nicely. Help!
What about other compatible species?

Also - To keep the bottom cleaner (and prompt her toward a larger tank w/ filter etc) I was thinking of adding some of the small shrimp or other 'maintenance fish' - any suggestions?

I was reading thru your other posts - GREAT information! Thanks!!

Answer
Hi Bob;

If the betta has long fins it is male. However, males and females should not be kept together all the time. The female is introduced to the male's tank when ready for spawning only. If the female is not ready to breed or after they finish breeding, the male will chase her away and can kill her. The male takes care of the eggs and the babies and he wants no intruders, including the mom. It is sometimes possible to keep multiple females together, but the tank must be 10 gallons or larger to give them room to get away from each other. Sometimes even females fight and sometimes a female will beat up her mate too. Crazy fish!

The one gallon is just too small for anything more really. Especially if the bowl has no filter or aerator. Even "cleaner shrimp" or other helpful creatures add their own waste and use oxygen. Here is a list of links to more info about bettas, possible tankmates when she gets a bigger tank and what they like and need;

http://www.klsnet.com/betta.html
http://bettas.fishjunkies.com
http://www.siamsbestbettas.com/care.html
http://freshaquarium.about.com/cs/anabantids2/p/betta.htm
http://americanfishguy.tripod.com/bettacare.html
http://www.healthybetta.com/
http://groups.msn.com/TheBettaObsession/
http://www.bettatalk.com/

At Your Service;
Chris Robbins