Betta & Pygmy Cory Dilemma

[CrazyDiamond88]

I've had my tank up and running for about 6 months now. I started off with my betta, Kasai, and 11 pygmy cory.

Since then 1 cory died randomly, no idea why. And then recently another one died, also have no idea why.
 
Now, as some of you know from my thread in Tropical Emergencies, another one is looking quite sick, clamped fins, not swimming much, lying awkwardly on its side etc.
This seemed to happen after a rescape, which I did after the 2nd pygmy died, with the aim of making the tank more comfortable for them with more hiding places.
 
My water parameters are fine. So it was suggested that perhaps Kasai was harrassing them.
 
To be honest, I never saw the betta bothering them. They would sometimes swim quite close to him and he would ignore them.
At night he is in the breeder box while they feed.
 
I just saw now that he nipped at one of the cory and the cory sped off as fast as possible. That was upsetting to see as he hasn't really done that before.
But now I'm wondering about the sick pygmy. It looks like part of its tail is missing and I'm wondering if the betta could be responsible for that.
Another one is also looking a bit poorly with a similar part of its tail missing...
 
So I'm wondering what people think, if the betta could have done that to the cory. 
And if so, what should I do? Should I move them out of his tank? I'm really reluctant to do that. I'd have to sell them or give them away as I have no other tank for them.
Plus I do love watching them swim around...
 
At the end of the day though, I wouldn't want to be hurting them so I'd do whatever was necessary.

 

[Lillefishy]

Pygmy corys tend to occupy the middle levels as well as the bottom of the tank so yes I think your Betta could be nipping at them when they invade his space. I would take them out to save any more injuries or deaths

 

[CrazyDiamond88]

You think I should just do that?

I'm not sure what I would do with them... Sell them?
If anyone here wants them and lives near me (in sydney) they could get them I suppose.

 

[CrazyDiamond88]

It would be good to have some more opinions before I take such a big step

 

[Meeresstille]

What if you got a 5 gallon tank, just for your Betta? You then could find some more compatible tankmates for your pygmy cories!

 

[CrazyDiamond88]

I actually do have a 5 gallon tank spare at home.

I really would consider doing that.

But do you think he will be okay going from a 12 gallon to a 5 gallon tank? It makes me feel a bit bad downgrading him like that.

 

[Meeresstille]

I think he will be just fine! Create a really neat little jungle for him, an interesting new territory to explore, and living stress free will be an upgrade for him.

 

[CrazyDiamond88]

Hm I dunno. In a way it's such a neat idea and it solves all my problems.
Plus it means I can get more cories and maybe some shrimp for that tank.

On the other hand I'm just not sure about moving him to a smaller tank.
I know I could make it really nice for him but his space will be less than half what he has now.

Obviously the other option is I get rid of the cories....

 

[Meeresstille]

Separating the two species is the best for both of them. A decision is always hard, and I can understand why you'd feel bad putting the Betta in a smaller space. Maybe you can put him in the 5 gallon temporarily until you found a good deal on another 10 gallon tank?

 

[CrazyDiamond88]

Okay I guess I'll give that a try.
Thanks for your advice

Down the line I would love to increase the size of the betta's tank.
And I'd love to get some more Pygmy for their tank.