Hi Ashlee and im sorry about the sfe
Tanks water Parameters? What was it prior before the sfe died?
What was the tanks salinity level at? Ph? Nitrates?
Never if something as this ever took places again, do you try in using a net to move the ill faith eel around for which would also only cause far more greater stress on the eel.
We found some fighting marks right where his head is, could he have died from the other bigger eel cutting into his chest and scrapping away all of his organs and making him internally bleed?
That young Ashlee is a bad No, No. never have a small eel in the same tank with a much larger one. This is possible that this other eel has put the bite on this young eel and caused it much injury and a great deal of stress. If you not mind, what size tank is this, and what size were both the eels? And were they of the same species?
Also, on adding any eel, specially a smaller eel that would most certainly die from a bite attack, add a second eel to what I believe be is a small tank, too small a tank for these eels. Also, eels will bite, even their mated partner when hungry and this not would make any differences if they were together for a good number of years. Eels are aggressive when hungry.
I hope I said it right as I wanted too, I been up since 5am and had my twins grandchildren all day, so im tired. If not understood, quote and ask what I meant by saying that. Sorry
Buddy