I have some and am still learning about them (Koi Angels). I think they can eat smaller tetras (like Neons) when they get full sized.
Here are mine when they were little guys.
Here is a bad quality pic - sorry about that.
You can see the same Blue Gourami, and how much they have grown in 2 months since I got them at quarter size, and they are about half grown, about old school dollar coin size now.
Also maybe you could get one if you have larger tetras. One I was going to mention on your other thread was Congo Tetra, the largest Tetra I believe.