NEWBIE QUESTION! What can a betta fish be tanked with?

.. My current male is a jerk, but I don't think he'd be nearly as rude in a 20 as he is in his 5, especially if he was the last to be added.

LOL!! *cough*.. almost lost coffee out my nose on that one..

I've got a male dwarf flame gourami in my 55 that's like that. A handsome bugger, but MAN what a puke. Luckily there's enough space, decor and larger fish to keep him in check.

In regards to the male betta, I've kept them in 10g's with either zebra danios or blood-fin tetras w/out issue. Mean ones I've had, but never spooky or skittish. They'd just about swim right into your hand.. or maybe bite you.
 
I've kept loads of Bettas with quite a variety of fish.
Typically avoid cichlids, other labyrinth fish, the larger barbs (Tigers are horrendous), larger Tetras.

Most small species catfish i find agreeable, along with Loaches. Neon, Rummynose, Cardinal Tetras all done well. Lemon and Silver Tip Tetras ive had hit and miss, atm i have a breeding group of Silver Tips so they pay no attention to anything.
Golden, Cherry, Black Ruby, Rosy and Cheque barbs ive not had issues with, and ive kept Crowntails abduction Halfmoons with them.
I have kept Leopard Spotted Danios with Bettas without problems, Zebra and Giant Danios have been buggers though.

Sharks ive also kept. Redtail, Red Finned/Rainbow, Black and Bala/Silver sharks all quite happily kept with them.

And then Live bearers. Mollies, Platies, Swordtails and Hybrid guppies (captive bred wild x fancy). Endlers and pure fancy guppies usually become snack foods.

Obviously, some of thsee will be too large for your tank, but some ideas for you :)
 
Bettas are ok with shrimp? That's good to know!
 
Not all bettas, no. As noted, the male betta I have now is a jerk and killed a large amano shrimp.
 
Over time, I've found that I cannot keep mystery snails in my 55g because the 4 female bettas pick at them. Same goes with any type of shrimp aside from ones that have gotten skilled at staying out of sight.
 
Mystery snails have big eye stalks, so are easy targets for fish that pick. Same applies to bladder snails and the 'batman' snails. Nerites, with smaller exposed spaces, are often successful additions since they don't present as much of a target.
 
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