Hello guest! Are you an Apistogramma enthusiast? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's a great place for Apisto enthusiasts to meet online. Once you join you'll be able to post messages, upload pictures of your fish and tanks and have a great time with other Apisto enthusiasts. Sign up today!
Probably depends on the species; but as long as it's a 48" x 18" footprint, with lots of cover, I think you could probably get away with it.
It's been my experience though, in that size tank, I typically end up with one male and two females, again, depending on species.
I've had pretty good luck with otos. I think hatchet fish would be a good choice for them; just realize that if the apistos spawn that the hatchetfish may prey upon the fry.