Last I checked the lack of documentation for firefish is a problem, especially how many features they claim to offer. Unless the community pick up this problem, I wouldn’t be expecting much any time soon.
Also, last time I played with the antennas feature I concluded that much of the power it tries to give you isn’t actually particularly useful. It’s best used to filter for hashtags and from particular sources, with the Boolean logic being helpful too. From I could glean it’s using a search that doesn’t require full matches with words, which becomes very noisy. So relying on a hash becomes necessary.
I may be out of date on this though.