What causes betta sororities to fail?

[ange]

I've never kept one but have seriously thought about it. What is required (aside from luck) to have success in a sorority for more than just a year or so? I've considered keeping bettas again because I'm falling back in love with them but have only kept them in solo/community settings. Would several females be at a better chance of success when they're in a larger tank with dither fish? With the information I have I feel like I'd personally be happiest with any betta (male or female!) in a solo or small community setting.

Factors in failure I've often heard:

• As the females mature and become egg-bound, their aggression toward each other increases.
• The tank is overstocked and there is not enough territory.
• The tank is understocked and there aren't enough fish to disperse aggression.

Edited November 3, 2020 by ange
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[Daniel]

6 minutes ago, ange said:

Factors in failure I've often heard:

As the females mature and become egg-bound, their aggression toward each other increases.

The tank is overstocked and there is not enough territory.

The tank is understocked and there aren't enough fish to disperse aggression.

I have kept male betta fraternities in the past when I was breeding a lot of bettas. In my experience, you can put 50 young male bettas in a 10 gallon aquarium and there will not be any serious fighting, just a few nipped fins. The reason a male betta fraternity works is that a territory or even any personal space is impossible and the signal for aggression is so overwhelming that the aggression response disappears.

So something like this is probably what allows a female betta sorority to exist. But I bet the genetics or 'personality' of the females also matter.

Even so having raised thousands of bettas, I would not be inclined to put a handful of mature female bettas in one tank unless I was willing to call off the experiment the moment serious aggression broke out. It would seem like a tricky thing to pull off (it is possible to get this to work as some people have success, but I bet this is a real crapshoot).

Other than intense crowding, the most import factor is room for retreat and sufficient cover. If the picked on fish can run away, and then run away some more and become hidden from the aggressor then it might work.

[ange]

27 minutes ago, Daniel said:

Even so having raised thousands of bettas, I would not be inclined to put a handful of mature female bettas in one tank unless I was willing to call off the experiment the moment serious aggression broke out. It would seem like a tricky thing to pull off (it is possible to get this to work as some people have success, but I bet this is a real crapshoot).

I really agree with this bit. I've heard of some people wanting to do it for the "challenge." I feel if I ever do put multiple together, it would be 2-4 in my 20L and have separators prepared (or moving them into one of the 10Gs that I irresponsibly picked up today).

[RovingGinger]

Right now I have three female bettas in my 40 breeder along with a mass of live breeders and corys and a couple oddballs. I’d say it’s medium-planted but lots of hiding spots in the rock work and decor. I think all three are fairly young, they are all random cup bettas from petco and petsmart. So far, they pretty much ignore each other and all other fish aside from being interested in the smaller fry. I don’t know if this will work long term or if I will need to redistribute to other tanks so I have no useful advice other than to say I am tentatively trying this and seeing what happens. 
 

The differences between fish are charming. To me, a betta is a large fish in a small package, from the way it acts to the way it seems to observe its surroundings. By contrast a molly is a small fish in a large package. Both charming but so different. I see the appeal of betta groups though, where else can you get such individual personalities and crazy color options? If I could keep males together I’d probably have 50 instead of 1 (I’m in no way brave enough to test any of that). 

[FrozenFins]

I would treat a betta sorority like a smaller version of African cichlids. I would do 6-7 females in a 15 gallon (maybe a 10gallon). More is always better! also have an eye out for the bully or the one getting bullied.