Betta in community tank

So I ordered a male betta, and the online store sent the wrong one out and are brilliantly going to send the right one out.
This means that I have a betta that I hadn't planned for and have no tank for (the 'right' betta - my daughter's first fish - will have its own 34l tank).
I have tentatively put the 'wrong' betta into the community tank, expecting the male gourami to have a nip like he had with another betta I tried in there out of curiosity.
Nothing! No nipping, no hero-worshipping, no following... can I expect this peace to stay?
It's a 145l tank with 4 guppies, 4 tetras, 2 dwarf gouramis, 6 corys and 3 balloon mollies in. In the photo you can see the 'wrong' betta exploring in the top left of the image.

Depends at a guess you may get issues with the Betta and the guppies if there males ,Some fin nipping. On the other hand you maybe lucky and have no issues at all. I have kept Bettas in community tanks with no issues but then they can cause havoc.

I have too kept a betta in a community tank with very little issues. Be wary of male guppys as said above because they can be a bit of a pain sometimes.

Also you might want to up your tetra count to 6-8 as I've noticed they are neon tetras and they like groups of 6+.

Besides the betta situation, may i also point out that you are keeping soft water fish together with hard water. This is not usually possible unless you have a GH parameter that sits bang in the middle of the low end of the hard water fish requirement, and top end of the soft water fish requirement.

The betta will not be happy in a community setup. Doesn't matter if they havent already succumb to illness through stress, or gone on a rampage. Its like being someone who hates being around people all the time, and sitting them in a room full of people for ever. Theyll become stressed and perhaps theyll show it, perhaps they wont. But they're stressed nonetheless and stress releases cortisol that knackers the immune system. Or they'll lash out kill a fish or two.

Again, be good to know your water's hardness (GH) as I would expect you may run into difficulties with that further down the line with either your soft water fish : betta, tetra, corys, or your hard water fish: guppys, mollys..

GH is between 7 and 14d, carbonate hardness is between 0 and 3, pH is 6.8.
I read that "Bubble nest surface area of B. splendens showed significant decline along the hardness series, reporting 75% decline at 900 ppm... In the hard water, 540 and 900 ppm, bubbles were blasted, and male fish was unable to rebuild the nest."
What does my hardness translate to as ppm?

Just found that "1 dGH corresponds to 17.848 ppm", so if we say my GH is 12d, then this is 213ppm... is this not fine for a betta?
"Hatchability of B. splendens declined significantly in higher hardness levels above 540 ppm reporting only 25% success at 900 ppm compared to 78% in the control (p = 0.006). The percentage larval survival of both species declined gradually with the increasing hardness level, reporting significant declines above 320 ppm (p < 0.0009)."
The "control" was 150ppm, so based on this research exploring the impact of water hardness on reproductive potential (from which I read 'happiness'!), 150ppm seems ideal, whereas 540ppm starts to adversely affect next building, hatchability and larval survival.
So with my GH at 213ppm, I would hope my betta would be happy? Unless I've got my maths wrong somewhere along the line, which is entirely possible...

The mollies might be happier elsewhere, of course. I took my guppies to the LFS this afternoon. I keep answering my own posts...

On_a_dishy said:

Just found that "1 dGH corresponds to 17.848 ppm", so if we say my GH is 12d, then this is 213ppm... is this not fine for a betta?
"Hatchability of B. splendens declined significantly in higher hardness levels above 540 ppm reporting only 25% success at 900 ppm compared to 78% in the control (p = 0.006). The percentage larval survival of both species declined gradually with the increasing hardness level, reporting significant declines above 320 ppm (p < 0.0009)."
The "control" was 150ppm, so based on this research exploring the impact of water hardness on reproductive potential (from which I read 'happiness'!), 150ppm seems ideal, whereas 540ppm starts to adversely affect next building, hatchability and larval survival.
So with my GH at 213ppm, I would hope my betta would be happy? Unless I've got my maths wrong somewhere along the line, which is entirely possible...

Click to expand...

You would need to lower the GH to 150ppm or so so that you can keep the soft water fish. You could go down the reverse osmosis water way but it can be a bit expensive. I forget which other options there are but I'm pretty sure there are.

I've tried it and it can work though I don't think it's ideal. It almost always involves growing stress and problems with either the betta or the other fish. Also, managing feeding is difficult as bettas tend to pig out and get sick in community tanks if you're not careful.

Sounds like you're addressing the hardness issues. As for the social issues, some bettas are OK in a community tank, and some aren't. My completely non-scientific observation is that they don't live quite as long in a community tank, which might be due to social stress. Sometimes they flip out and start abusing tank mates. So, watch him like a hawk and have a plan to remove him at the first sign of bad behavior.