I have crabs...with black claws

[TriggerFinger]

Found a molt this week that didn’t match my blue or red hermits...this molt was white with black claws. I’ve been scoping at night with a red light and I’ve seen two crabs I don’t want!! I found where people cut a plastic bottle, invert the top and put shrimp in it and they catch the crab. I have a small starry blenny and I’m afraid the blenny will go in the trap and get caught in there with the crab. Do blennys usually explore at night? Will he be tempted by the shrimp smell? Would it be better to use a tilted mason jar with a large opening?

I’m so attached to my blenny and would be devastated if he got caught by these crabs.

 

[ndrwater]

Either way will work. The blenny can find his way out if he goes in.
Blennies usually sleep at night