Hi everyone. I have a 10-gallon nano tank with live rock, some shrimp, and a sea urchin. On the back of the tank is a hob
filter with no media, and it just serves as a mini refugium and to cycle water around. My sea urchin somehow climbed over the waterfall and into the filter, and is just camping out in there indefinitely (he's been in there for over two weeks). It's impossible to feed him anything while he is in the filter, and if I try to remove him, he stiffens up and sticks to the inside wall of the filter. Is there any danger to him as far as not getting enough food? If so, how should I safely remove him and keep him from getting back in?