80 gallons

I have an 80 gallon tank, 3ftx2ftx2ft or 90cm x 60cm x 60cm (if ya nasty). I am looking for a few fish that will do certain things. I would like to have a small shoal of fish that could work as dithers (not anthias), a fish/invert that will eat aptasia(sp?) and a fish that will eat parasites...