I hydrogen peroxide dipped some zoa and paly frags that were being smothered by hair algae today, and I also spot treated one of the encrusted colonies with about 3ml of 3% hydrogen peroxide in the tank with the flow off. Now, my bubble tip anemone looks very unhappy, my sea urchin isn't carrying around seashells or climbing the glass like normal, and my cleaner shrimp is a bit lethargic and uninterested in food. I did a 25% water change in case it was the tiny bit of peroxide, but I don't have any more saltwater mixed up already to do a larger one. Did the peroxide do something to the inverts? The zoas I directly dipped and squirted look fine, yet the anemone on the other side of the tank is not looking good. I figured this was the thread to ask because this happened while treating nuisance algae, but let me know if I need to post this elsewhere.