Myriophyllum 'Guyana' is a recent addition to the aquarium hobby. Myriophyllum 'Guyana' is a green stem plant that tops out at around an inch in diameter. While many Myriophyllum species have been in the aquarium hobby for a long time, this species stand out for its much smaller form. This allows it to be shaped into dense, attractive bushes easily even in smaller tanks. It can provide great contrast to other non-green plants. It is a great filler plant that will grow side shoots to fill the surrounding free space.
Higher lighting conditions (90PAR+) and CO2 injection gives denser forms as it allows the plant to branch more profusely.
Myriophyllum 'Guyana' is a tad more sensitive compared to other super hardy larger sized Myriophyllum species. Planting them in a matured aquarium will reduce acclimatization stress. The plant gets algae more easily than more hardy Myriophyllum species and does better in tanks that are well maintained and clean.
While it takes trimming well, the bottom portions of the plant will still deteriorate after repeated trimmings, and eventually we will need to uproot and discard the deteriorating old bottoms, and replant fresh tops. This topping and replanting cycle needs to be done every few months to keep the bush fresh.
Myriophyllum 'Guyana' is tolerant of hard water.
Key success factors:
Higher PAR levels (90 umols+) allow for denser, more branching growth.
CO2 injection highly recommended - this species does less well than other Myriophyllum species without CO2 injection. The TC transition much better with CO2 injection while matured plants are more robust.
Plant in a matured, cycled tank. This plant can be vulnerable to algae as its leaves are delicate.
Regular fertilization maintains bright, fresh green leaves.
Regular, strategic pruning to keep it in good form. Easily reaches the top of most tanks given enough time.
Trimming & propagation
Myriophyllum 'Guyana' is a fast growing stem plant so propagation is easy; cut off top 3 to 4 inches of the stem and replant, leave the bottom portion to sprout new shoots. After many trimming cycles, the bottom portions of the plant will deteriorate, and this can be seen as the lower stems get bare. Older deteriorating growth is vulnerable to algae and takes a longer time to recover. This can lead to less dense or uneven bushes.
The bush can and should be refreshed periodically by uprooting and discarding the old growth, followed by clearing the patch of aquasoil of excess detritus, then cutting off and replanting fresh new tops (3-4 inches) of the plants. This technique can be used to refresh most stem plant bushes that face deteriorating bottoms after some time.