harlequin rasbora maybe. They tend to be orangey pink
How big are they? Maybe a penguin tetra.
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I wouldn't put money on this bet but I believe they are the Rasbora (Trigonostigma somphongsi). Check out what you find with this name and keep us posted please. They look so much like a mutated Black Neon that I was almost sure they were a tank bred mix but then I looked up rasboras in my books and think I found it.
You are absolutely right my friend. They are indeed Trigonostigma Somphongsi. I'm really enjoying keeping these fish at the moment so much so that I'm breeding them.