Betta in a community tank question.

I have a 18 gallon tank, and I had 2 guppies (one male and one female), 2 leopard danios, 2 aquatic frogs, and a plecostemus. (and a black mystery snail). I had no problems, really.. after a coule nips to the danios fins, he left them alone. The only problem, was after the fact, they all got ick, and my 2 guppies died, and my betta got it pretty bad. He's just fully recovered recently, and, I plan to put him back in the tank as soon as the cycle is finished.
 
Bettas behave differently from one to the next. I've had like 6 and every one of them is unique, "personality"-wise. I've had 3 fat honey dwarf gouramis in a 10 gallon with my betta and did very well together. They'd chase each other every now and then, but not the betta.

Bettas and zebra danios? Not sure. I know they are very active but try it and see if any fin nipping occurs. I've had bettas with cardinal tetras before with no problem. The cardinals are a little more shy with the betta around.

Currently I have a betta with lyretail hifin swordtail, and 3 semi-fancy guppies (not feeder guppies, and not show winning guppies). No problems at all. You'll just have to try it and see.
 
Oh yeah I have to add that I've had like 2 extremely aggressive bettas before that didn't like any other fish no matter the size or finnage. I exchanged them =)
 
I had a Beta in my tank. Had to take him out because the Danios would pick at it's fins.
 
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