Leave them in the tank. The pair won't produce any more fry than that if one batch makes it to adulthood. You'll realistically end up with like 10-15 ish adults in the tank long term, all will periodically spawn, but few of their fry will make it to adulthood, especially if there aren't a lot of hiding spaces. The bichir and oscar will not eat them... Maybe a few babies here and there but once they make it past like 2" they're safe from anything bigger.
