The South American Leaffish
Monocirrhus polyacanthus
(Heckel, 1840)
What are they and how big do they get?
The South American leaffish are part of the Polycentridae family. They are also known as the Amazon leaffish.
This species is native to South America and is found in various countries. It has been recorded in Bolivia, Brazil, Colombia, Peru and Venezuela.
A size of around 3-4 in (8-10 cm) can be expected.
What temperature can they be kept at?
South American leaffish are tropical and do well when being maintained at around 22-28 °C (71-82 °F)
How many can be kept together?
Aim to keep them as part of a group - we recommend 6 as a minimum, but the more the merrier if space allows.
Water parameters?
pH - 5.5-7.5
dH - 1-10
What do they eat in captivity and how often should they be fed?
The large tube-shaped mouth used for sucking in prey at lightening speed!
It is suggested that to maintain this species, they must be fed a diet of live fish; however, this is not accurate.
These fish can be kept, maintained, conditioned, and bred by feeding them glassworms (phantom midge larvae) that have been gut-loaded with newly hatched baby brine shrimp before being given to the leaffish. Live 'feeder' shrimp are also readily accepted.
With persistence, it may be possible for the leaffish to accept a diet consisting of frozen or thawed foods. Occasionally, they may also accept dried foods, but this should be accepted as a rarity rather than the norm.
Daily feedings are recommended; however, going a day or two without food will not cause any harm.
Which tankmates are recommended?
South American leaffish are shy and do best in a species-specific aquarium.
The aquarium?
The aquarium can be furnished with tangles of wood and a liberal scattering of leaf-litter.
Floating plants can be used, as they will assist with water quality and help to diffuse bright lighting.
Will they breed in captivity?
Eggs on the underside of an artificial plant, being guarded by the male.
Yes, when leaffish are conditioned they will spawn on a regular basis.
Courtship involves the male and female shuddering their bodies to each other.
Egg laying typically occurs under a leaf (real or artificial). By taking turns, the female will lay the eggs whilst in an upside-down position, the male will then take his turn in an upside-down position to fertilise the eggs. This process repeats until the female is totally spent of eggs. In our experience, the egg count has been approximately 100-150. Once spawning is complete, the male begins guarding duties.
The eggs should begin to hatch from around 3 days or so. After the eggs have hatched, the fry fall to the aquarium floor amongst the leaf-litter. Several days later you may begin to see free-swimming fry. At this point a turkey baster can be used to remove the fry to safety and raise them separately.
For increased yield, taking the eggs away on day 2 for artificial incubation may be the best approach. Tiny foods will be required for the first few days of life, and these may include paramecium and infusoria. Newly hatched brine shrimp is eagerly accepted when the fry are a few days old.
As the fry grow, their food size can be increased accordingly, with a transition from baby brine shrimp - to daphnia - and then to glassworms.
Other notes
South American leaffish have a reputation for being a hard fish to keep and feed. If you're willing to buy regular supplies of glassworms, there is no reason that you shouldn't be successful in maintaining and breeding this species.
Providing that parameters are adjusted slowly, this fish has shown to be tolerable to a wide range of conditions, such as spawning in hard and alkaline conditions.
It is a master of disguise, perfectly resembling a fallen leaf and remaining hidden, even when in plain sight!
Conclusion
They are often exaggerated as being challenging, but this perception is not justified. With some commitment and the right food sources, they can flourish, leaving you to question the concern surrounding them!