So i've been hearing different things about clean up crews - are they really beneficial for your tank because someone brought up the idea that they are cool to look at but basically poo out what they eat. Is this correct? Do cuc's still 'clean up'?

Hello, I need to ask whether this collection of fish can go together in my tank!! I have this collection of fish which I am intending to buy and install in my tank. But I do not know if they go together and can get along!! Well here it is: Fish wise: B&W Heniocus Butterfly Long Nose Butterfly...