Agreed, cleaner wrasses in general do not have a good survival rate in home aquaria unless they have a large population of fish to clean and even then, it's chancey. I have seen a few that eat prepared foods and flourish but I wouldn't want to bet the fish's life on it.
In a 45 you could look at some of the fairy wrasses (although some like the Scott's, can easily get to 5-6"), some of the flasher wrasses, six-line wrasse, Pygmy arrowhead wrasse or possum wrasse (one of my new faves) wrasses in the Halichoere genus generally stay smaller as well.
Make sure you look up the scientific name of any of the wrasses you might want to purchase. Some of them get huge, as well as destructive, in a reef tank.
Scott Michael's Marine Fishes Pocket Guide is an inexpensive book and a "must have" when shopping for fish, IMO.
With regards to the cleaner wrasses, I have had tremendous success now since I found a feeding regieme that seems to work for me, at least for the common cleaner wrasse.
I grind up beef heart in the blender till it's like baby food, and that gets the wrasses eating well. As they grow, I increase the size of the food and mix in other foods as well. If I don't sell them withing 8 months to a year, I can even get them eating spirulina flake food.
I used this prepared beef heart to feed to a Hawiian cleaner wrasse that an LFS brought in to sell, but it wouldn't even look at the beef heart, or any other food.
For sure, that's one cleaner wrasse I won't buy.
All the regular cleaner wrasses that I've purchased, eat beef heart with no exceptions.