yes, probably he will get eaten, and you alread y have way too much in there now, sorry but it is only a 46 gal, and you have several larger fish
how'd you get them all in there as it is, wow
they will grow, and even if small they are still larger fish, and you need ot figure their adult size, not he size when purchased
sorry, but it seems to me you are well overstocked now, my reccommendations would be to get a much larger tank, or a few less fish, besides, if you already have an ick problem it is just that a problem, odds are against the cleaner,plus the fact that the cleaner wrasse will only clean the willing victim and being a new guy this may take some time and the cleaner is also succeptable to the same parasites, i would do something els and faster than buying a wrasse
if it is not a real bad problem, you can try kyolic garlic from gnc, but this will only help mild problems, it is much better for prevention
welcome aboard, your name seems new to me