You can, but you don't want to use minnows as feeders - Guppies, Mollies, and Ghost/Grass Shrimp are recommended because they're brackish water critters and have a much better nutritional profile for saltwater predators. Also, it's likely not a good idea to keep predators their live feeders - the predator experts suggest that feeding them too frequently can cause serious health problems that lead to the predators dying fairly quickly (a "fast/gorge" feeding schedule is recommended).
My post in the thread linked below is a lot of info to take in, but it's packed with good info on keeping and feeding predators, but if you're not up for reading all of it, I'd strongly suggest at least reading lion king's links in the quote below:
I went and bought ghost shrimp a krill. The guy said to mix the krill and ghost shrimp together. The seemed to only eat the ghost shrimp. Only had tge lionfish fir a couple of days. I assume no reason to worry? Krill is okay but not all the time. Neither one of my lions likes krill actually...
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