long island sound

I introduced three new sea urchins to my long island sound tank yesterday. Floated them as I thought was appropriate amount of time (about 4 hours) I also added a couple mummychugs and two green crabs. Upon returning to my tank this morning all three urchins are flipped on their "backs" with...

Hello, I have an established ecosystem in a half circle 35 gallon salt water tank. I have a 4 level canister filter. I HAD 5 hermit crabs , 4 decent size and one smaller than your fingernail (all with shells) I entered my 5th grade classroom today to find remains of a molt but no crab. What...