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Nerite snails do a great job on algae. They won't reproduce at all in freshwater. Ramshorn snails also do a great job on algae and will reproduce. Apple aka mystery snails are good at scavenging leftovers, as are ramshorns, and malaysian trumpet snails.
Ramshorns don't really get out of control as long as the tank isn't over fed. IME they don't reproduce as fast as pond snails. If the bichir will snack on them you should be fine. I wouldn't want them around with nothing eating them though or with time the numbers would climb too high.