Use a basilo. Isolate the eel you want by killing the others, you can try to tame multiple at once but it gets hard to time the shocks. You can’t not aggro them, but repellant doesn’t work, just let them attack. The eel will shock, then bite a few times as it charges up, flee a bit, then come back and shock again. Wait for the shock to be over, dismount while it’s biting your basilo, feed it biotoxin, then remount the basilo for safety and wait for the next feed. Seems to take about 2 shock cycles for a low level to want the second feed. I was able to do this without taking any damage or torpor on my character.

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