If you read threw a few other... dozen times this has been asked.. the answer is still the same

As juviniles yes.. sometimes they can be housed together. Krawnik as they mature they will likely get more aggresive, Not less aggressive. and Your TT showing signs of aggression already is not a good sign. If the TT backed off once the fire did.. they might be compatable.. but the fact the TT is continueing his aggressions. I'de say you have a 99% chance the TT will eventually kill your fire eel. Or chase him bad enough your fire eel commits "carpet suicide" as another MFKer calls it. in a 500gal + tank with many many hideing spots for each eel you might be able to pull this off. a 125 might house a Fire eel OR a TT for life. Might... Both are the two largest false eel species, and notoriously aggressive towards con-specifics. There are a few MFKers here who keep more then 1 fire eel together. But I have yet to see anyone keep more 'n one TT in a tank. 'nore and Adult TT and Fire eel in the same tank. Theoretically with enough room for territories yes? realistically? no. One eel usually kills the other.. and usually it's the fire eel that dies.