Whoa whoa whoa, I was reading through this thinking about peppermint shrimp prices in Canada, but then I read you have 3 brittle stars?
I had a thriving stomatella snail population before introducing a pink brittle star. Never again will I make that mistake. Took years to find more stomatellas and get them breeding.
Okay, that's one thing, but you mentioned a green brittle star? Does it look like this?
If so, take that thing out. It's a downright fish-killer. That's from experience. For more information, read the article on predatory brittle stars here (towards the end):
https://issuu.com/reefhobbyistmagazine/docs/88fee0421317424e4469f33a48f50cb0-ve
Remember when Reef Hobbyist had some cool, out-there articles instead of "here is my tank" articles?
I also suspect my pink one killed my hi-fin goby. He sure put in the effort at least. It's a terrifying thought. These guys lift their bodies up on their legs, wait for something to pass underneath, and then ensnare them with a downward twisting motion with their legs. It gives me the heebie jeebies when inverts eat verts. More power to them though!