Thank you everyone for the welcome!
I'll repost yesterday's photo. It's a pic of my tetras, I've just got a small freshwater tank that's been going with no troubles ( deaths or disease) for the last year! Then yesterday the power filter died, poor fishes were gasping for air. I found an old air pump and air stone and they survived until today when I bought a new filter.
As of this evening they are still scared of me