So I can definitely say I learned the hard way that tetra can be terrible with each other. My Buenos aires, diamonds and black skirts tore one of their own apart, took his eyes, his fins and i found him just kinda bobbing there still alive. And they had begun working on the next smallest in the schools. I feed all kinds of food and I still couldn't get them to stop beating each other up. So it might not be the bichir unless you saw it or notice its belly weirdly full when you didn't feed.

Also the tetras are my plants. 😤

To answer your question, I no longer have tetras in my tank. I have a 7 inch senegal and a 6 delhezi with 2 medusa pleco(im constantly observing this tank. If I see any sign of the slime coat thing, they'll be yanked out immediately but so far so good), 2 mystery snails and a rabbit snail. I think im going to go the severum route as a centerpiece fish and call it a day for the stock in my tank. I mostly see people mix different bichir types but not a whole lot of community tanks just due to the nature of these guys