Yeah, I agree about the anemone. We have a big one in our 90g and the amount of waste they produce is ridiculous. I wouldn't put one in a 10g, I think anyone that saw them poop would agree, lol. They can also be a hazard since if something irritates them they'll move around your tank and end up stinging everything.
I also wanted to add to really really research if you become interested in a certain fish. Looks can really be deceiving in SW fish and some babies look nothing like that as adults. I got interested in some convict blennies for my 20g. They look like cute like snake-like fish that don't get over a couple inches and it turns out they turn into 14-18 inch monsters that looks nothing like the babies and will burrow deep into the sand and potentially knock over all your rock work.
I also wanted to add to really really research if you become interested in a certain fish. Looks can really be deceiving in SW fish and some babies look nothing like that as adults. I got interested in some convict blennies for my 20g. They look like cute like snake-like fish that don't get over a couple inches and it turns out they turn into 14-18 inch monsters that looks nothing like the babies and will burrow deep into the sand and potentially knock over all your rock work.