if she's feeling very intimidated you might have to say goodbye to the rest of ur tetras and possibly even one of ur oto's, eventually when she's feeling she's made her point she'll hog the food, attack all fish that beg and, excuse my language, be the ***** of the tank UNTILL!! evetually (about 4 months) she will calm down and come to befriend the other fish and become a tank member so its ur choice, rehome or not (there is always the chance the killing has already stopped
I'm thinking not.
First off, if that sort of behavior continues for 4 months, there's a problem. It should only be a week or two at best.
Second off, leaving it alone is not the best of the best options. If a fish is attacking others to the point where they're dying or hiding behind the filter or heater in a corner of the tank, there are a few methods to take. I found one particularly effective.
What you do, is remove the aggressor from the tank into a large bowl of the tank water for 30 minutes or more.
Remove and re organize the decorations, maybe shift the substrate a bit while the fish is removed. This will break the territory bonds, and make the aggressor feel like she was just put in a different part of the river, thus more accepting to tetras and smaller fish, and less relentless to other territorial fish which are already in there. don't throw the fish into the tank right after you redecorate. Wait just a little while first.
This will help more than waiting 4 months for it to kill everything.
When my female convict acted out, I had to remove it completely from the tank. But that's a convict, not a ram. I have a feeling that if I waited 4 months with -any- fish for it to throw a fit, especially if there were already casualties, there would not be any other fish in the tank. And it wouldn't stop yet.
On another note, my cichlids have always been more aggressive toward the new arrivals, not the tank as a whole. I'm curious about why it's going after everything, even after being the last added.
you did the right thing in adding her last, but it might just be true she's a total psycho. I know how that goes.
Since rams in particular tend to be pretty docile (which is why I find it interesting that you rams actually attacked something) I think the rescape of the tank will be effective.
Since she was docile at first, it might be so that she has claimed a part of the tank, and doesn't want other fish going at it. Since your tetras are small, as are the ottos, they might just be less tolerant of the aggression.
If things don't work out, I'd rehome it and try another. Like I said, rams tend to be docile. It's surprising yours is getting aggressive. I've never had aggressive dwarf cichlids before.
Good luck