Could someone please recommend some dither fish for my mixed monster tank?

Hi guys,

I currently have a 4' x 2' x 2' with a community of oddballs.
The tank contains;
4-5" Tiger DAT
4" Senegal Bircher
3" Leopard Bushfish
3" African Butterfly
4" Channa Gachua
4" Angel Fish
4" bala shark
And a couple of corydoras

Everyone is getting on well and eating, behaving normally.
I'm thinking of adding a few dither fish though just in case any aggression or territorial disputes were to break out.

What could I use, don't want anything that gets too big, as I'd like to keep them in the 4 footer long term after the other fish have outgrown it. But they need to be big enough so as not to be a meal for the dat\snakehead.

Any advice appreciated.

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Its still a relatively new setup, dats only in a week or so. Thought some dithers might be a good preemptive step.
Better safe than sorry.

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The bichers a long way off eating them. He struggles to swallow even half a hikari massivore pellet.

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Why lose the DAT? He's been 100% peaceful so far and none of the other fish seem to pay him any attention?
Is that likely to change?

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