It's a bit late, but honestly, Wrasses are awesome fish provided you do your research and get the right one. A Melanurus Wrasse would be a little bit tight in a 50 gallon (then again I currently have a young one in my 36 gallon), but it would be brightly colored addition and with rare exceptions people have great experiences with them. I got a really young one and it has been the only fish I have added in 4 attempts that hasn't caused me aggression issues. I have had to Remove a Flame Angel, A Red Head Salon Fairy Wrasse and an Occ Clownfish due to aggression issues. The Melanurus is bold and very active but doesn't mess with it's tank mates. That said, my clownfish was an absolute butthead to all my fish and pushed the wrasse around for a while and then the wrasse spent the next day beating the crap out of the clownfish (it actually grabbed it by the tail with it's mouth and gave it the rag doll treatment) and then left it alone other than the occasional reminder nip when it got too close. So IMHO they are the perfect balance, active and peaceful and won't seek out a fight but they won't be pushed around by a comparable sized aggressive fish either. The only downside to them is that they will eat some snails and crabs. Given everything else they offer though it's a fair trade.