a knight goby, dont have yet, bumblebee goby i have already. and a male and female guppy, dont have yet, why a guppy because i wanted something to breed. and the gobys will eat some of the babys.
in brackish water.
I have 14 Bumblebee Gobies in a 60g with a Knight Goby. He never gives them a second look, despite them being everywhere. He just makes it hard for them to get a lot of food, but targeted feeding solves that problem.
If the above posters are all speaking from experience, I'd listen to them. I might have the one Knight Goby who doesn't fit the norm.