What are some interesting fish to add to my 40 gallon tank?
You have a good mix going there with the exception of the ghost knife and the clown loaches. The clowns are peaceful fish, but will get WAY too big for your 40 gallon, they need at least a 75. The ghost knife needs at least a 120, they get HUGE. Also, they are strictly carnivorous fish and will eventually eat everyone else that is smaller than them. Take the ghost knife back to where you got him from. As for other tank mates, you have a lot of options to choose from. German Blue Rams are beautiful and peaceful fish, but can be hard to keep. Bolivian Rams are a little spunkier, but I keep one in my community tank with rarely any issues (feeding time is the only time he gets snippy). You could also put in a couple of dwarf gouramis; they have 3 basic color variations that are very pretty, my favorite is the powder blue. Stick with dwarf gouramis though, other breeds of gouramis will bully your community fish. You could get any one of the tetra species, also the smaller danio species will