How do I choose a healthy Betta from out of all those tiny containers?

My girlfriend would love this topic because she loves her bettas. The things to look for, as with any fish, include:

Does it appear healthy: full, but not bloated belly, no parasites, no fungus, no tattered looking fins, clear eyes, and vivid coloration.

Bettas are pretty lazy sometimes so activity level would not always indicate health, but make sure the one you pick out is responsive. Sometimes I like to pretend I am putting food in there death trap to see if they respond, usually that means they are feeding well.

If they are constantly flaring at the other bettas this could also indicate good health, but you may be getting an aggressive fish, which could be bad. I had one betta in my community tank that would flare at all fish and chase and nip at them so watch for temperament.

Female bettas are beautiful also and frequently more community friendly. However I have had problems with females getting egg bound. I do breed them sometimes to relieve this situation, but I quickly run out of grow out space.

If I have left anything out I am sure somebody will post after me, or I can have my girlfriend look this over and post again. Other than that have fun finding your new betta.

I think you either get lucky or you don't. Aside from obvious signs of disease just pick the one you like the best.

Look for ones that move when you pick them up, and ones that are flaring.

Check the bottom of the cup. There should be no food or poo. If anything, a little poo. The betta should typically not be floating, but hovering in the middle or laying on the bottom.
Look at it from the top. The head should be contour with the body. Not bigger or smaller.
As stated, watch for obvious signs of dropsy, fungus, etc. These fish are on death's bed more often than not.
Make sure you like it. Don't get a healthy betta with ugly colors you won't appreciate. You will provide better care for fish that you like, so get one that moves you.
Females are a good option as long as there are no males within sight of her tank. The eggbound issue is real. My favorite betta died from what I'm pretty sure was a case of being egg bound.
Bigger is not better. Smaller equals younger equals better adaptability, immune system and vigor as well as lifespan. Go for the small betta. His water is cleaner, too.

Yes, aggression and possibly mating interest if done suavely. The gills fold open to make the head look bigger when viewed straight on. It is a little creepy at first to see the inside of the betta. Have fun finding a healthy betta!

Here yah go. This is one of my bettas

I bought these two females at Petsmart. I'm no expert, but I think they're pretty nice. They live together and mostly get along. There isn't much outright fighting, but they flare at each other and kind of dance around each other alot.
(I threw in an extra picture of Turquoise because she's so cute.)
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