Need help!!
 

90 Gallon reef tank, bought a velvet nudibranch that eats planaria. Has been eating just great.

Came home, saw most of my filter feeders closed and immediately looked for my velvet nudibranch as I understand they are toxic. Looked at him, he's still moving, he still eats, but he has a large laceration to the entirety of his body.

Question is, do I remove him or let him heal in my refugium?

if it was mine it would be gone , if it had to stay i would def be running new carbon and doing a water change:)

+1 for carbon and water change.

The flatworms are toxic and when your nudi got chopped up it may have released some of their toxin. I don't know whether that specific species release toxin when attacked.

If it is moving and eating I would not throw it out.