What are the dimensions of your tank?
It partly depends on this. Everything isn't about gallons-- real estate (in terms of tank bottom area) makes a difference and this should be a question before giving hard advice.
A number of geo species do just fine as male/female pairs in a tank-- if they're not too cramped. It can also help if they're not alone in the tank. It's possible for two males or two females to work, though it's true they'll tend to fuss with each other, all the more so if their isn't a larger, more dominant fish in the tank for them to worry about.
I'll say this-- on occasion what I see in tank size discussions in groups with international members is we have the luxury of comparatively less expensive tanks, equipment, fish, and sometimes more space to fit them in our houses in some countries than others. In effect we become spoiled and trained to see tank size a certain way, without understanding that in some places they're very adept at successfully fitting communities of fish in tanks some of us would deem to be too small. Like it or not, this is a fact of life.
That said, 41 gals is on the small side and may or may not work for what you're trying to do. Red head geos vary in adult size, some might max at 6 inches, but they can get larger. So, again, not a hard answer, depending on this and your tank dimensions. Depending on tank dimensions a pair of red heads may not work or you may be limited to adding some tetras or something similar, maybe a small pleco or catfish, or you may get away with a couple of smaller growing angelfish, or even a small growing cichlid or two.