Tomorrow I’m going to Petco to pick up seachem phosguard for my annoying diatoms algae (it keeps coming back! I’m cleaning it every day!!). As you know, I love the looks of the yellowtail damsel, and if I can, would love to purchase one. The Petco I’m going to got a new shipment of yellowtails, and it’s very tempting to get one. I love the color and the activity one would bring into the tank. The clownfish I know do pretty okay with them, but I’m worried for the firefish. He has an established territory, and hides there often. He is getting comfortable to come and swim around, and I don’t want to take that away. If the damsel will really be a nuisance to the rest, I won’t get it, but what are your thoughts? Is it safe?