I have a 30 gallon tank with 12 celestial pearl danios, 12 harlequin rasboras and 6 kuhli loaches, can I add a female betta?
I understand that CPD are very shy fish and I don't want to stress them out by the betta being there. I also don't want the betta to be stressed by all the small fish.
I know I can physically put them in the tank together and it will most likely be fine. I try amd give my fish the best environment possible, planted tanks, biotope inspired with leaf litter and botanicals. I want to know if you think the smaller fish will be as happy with a betta in the tank as they would be without her there and if the betta would be ok with it too or if she would be happier alone?
Thanks, hope that all makes sense
Personally I also think both sets of fish would be happier in different tanks. Female bettas are solitary travellers in the wild - only spending long enough with a chosen male to mate and lay eggs, then she quickly makes her escape, or he drives her away- which is why betta breeders are so careful and have to remove the female from the tank as soon as they're done with the egg thing, since she can't escape from the male in a tank the way she would in the wild, and the male may kill her otherwise.
Celestial Pearls are a shyer species, and having a much larger, more aggressive and predatory/territorial fish like a betta in there is highly likely to cause them stress, even if the female doesn't actively chase and hate them. We can't see and measure the hormones and chemical signals given off by fish in our tanks, we only know some from lab studies, but a lot is communicated that way, and believe me - fish are very aware of what other fish are nearby... being so vulnerable to predators, a much smaller fish, I wouldn't add a betta in there for that reason alone - the stress factor, even if all appears well, as it sometimes does, at least at first.
But, that's just my opinion, and people can and have kept a single betta in a community tank, so it'll really come down to a personal choice at the end of the day. I'd just strongly recommend getting a spare 2.5- 5g tank to have spare and ready if you do, just in case an emergency evac is needed.
It's also worth remembering that the fish in store are juveniles, and juvenile behaviour isn't the same as mature enough to breed adult behaviour, in most very species on the planet, including fish. Betta "sororities" seem to have come about especially when people buy a group of females from the same batch, since when they're first hatched and begin growing, the females can be kept together for a while without attacking each other the way males would. That early "we're all growing in the same bit of water her right now, but we'll all go our separate ways once big and strong enough" immunity that people hope will endure if they put five or more females together, and call it a sorority.
And it sometimes seems to work! For a while. But then you see the posts a few months later, once the females have matured, becoming a lot more aggressive and territorial towards each other. Because they don't live in female groups forever in the wild. They're solitary travellers that go their own way once mature enough to begin breeding. So they mature, cannot leave, and begin to fight, bully each other, stress each other out, and fish begin dying, usually.
Same thing can happen if you add a young betta to a community tank. Might seem fine for a few months, although we can't test the stress levels of the fish to know for sure whether having a territorial, solitary and sometimes, like with CPDs, much larger fish trapped in the same space with them. But we see a lot of threads and posts here where people have declared that their betta had been fine with his/her tankmates for ages, before the tankmates began vanishing, or were massacred overnight, and they're shocked, because everything looked well to them, at first. So my main advice is "I wouldn't, I don't think it's worth the stress or the risk", but that if someone is gonna try it, either a community including a betta, or a "sorority", is to have spare tanks ready, just in case. But if you're willing and able to have a spare 2.4-5g, might as well just set it up as a perfect tank for a betta to begin with!
Maybe consider a different centrepiece fish? A honey gourami maybe. A lot of the same benefits as a betta, much more peaceful and community friendly fish, ya know? Or I'm sure there are many other options others could suggest!