Triggers are notoriously evil. I know, there are exceptions, but how often do these exceptions occur? I'll never know, because as much as I love to look at them, and love the thought of having one, I refuse to take the chance that it will bite the heater tube, or that it will scrape its' teeth on the aquarium...
I wouldn't suggest having them together, but if you're really set on putting a trigger in a 60gal, I'd go with either the pink tailed (Which i feel would get a bit large, but if you got it small, and someday plan on getting a larger tank...) or the picasso (humuhumu). Both are fairly passive in terms of triggers...the picasso is the right size for this tank you're setting up. Make sure that any crustacean (cleaner shrimp, CB shrimp, emerald crabs, etc) that you want in that tank hit the rock before you put the trigger in...a guy I met via my LFS told me a story about his clown trigger and an emerald crab that I will always remember, and I'll sum up for you.
He bought a clown trigger, and it was the first thing he'd put into his tank other than some mushrooms and some cucumbers (slaps forehead) about a week later, he bought about ten emerald crabs...somewhere around the 5th to fall into the tank, the clown trigger decided he couldn't take anymore and *must* eat at least one, swam over, and got a face full of emerald crab...the smart little crab however, didn't feel like being lunch that day, and grabbed on with all legs and claws flailing around. the guy said that he couldn't help but laugh because the emerald crab was stomping a mudhole in that triggers butt and walking it dry...he laughed all the way until he realised a 25 dollar crab was about to kill a 150 dollar fish. The whole time this crab was trying to take this triggers' eyes out, the trigger was *still* trying to eat him. Instead of trying to smash him or get him off his eyes..he wanted to eat him. Stubborn and mean.
