ARe you guys saying it's bad to have hydriods in your tank? I have a few that look like little red featherdusters.
They are bad if you touch them or they touch anything else. They are related to jellyfish and will sting you and corals. I was stung by mine. Nothing major but it did burn for a couple hours. Another nuisance that will spread in your tank.
"Most hydroid stings almost immediately produce small red bumps that remain itchy and painful for hours. Sometime victims feel a prickly sensation. This rash can last up to 10 days. Skin with hair on it usually has less reaction than bare skin. More-severe sting reactions are blisters, swelling and hives.
No cure exists. Rinse the sting with water, (salt or fresh), to wash away any adhering nematocysts, then apply ice for pain. For persistent itching or skin rash, try 1 percent hydrocortisone ointment four times a day, and one or two 25 milligram diphenhydramine (Benadryl) tablets every six hours. Diphenhydramine may cause drowsiness so don't drive, swim or surf after taking this medication. Both these drugs are sold without prescription.
If the rash worsens, allergic symptoms occur, or a feeling of generalized illness develops, see a doctor immediately. "