Arrow Crab Concerns

[Jack biocube 32]

Around five o’clock today I added an arrow crab to my tank and left. When I got back he was at the top of my tank eating the seaweed from my veggie clip. Just wondering if this normal behavior, if it happens often, and how to prevent it so I don’t wast seaweed

 

[Uncle99]

Cheaper than snails….
It’s an opportunistic feeder, not picky at all.