Can Common Duckweed and Congo Anubias Grow Together?

Common Duckweed and Congo Anubias share a workable water window around 22 to 28 °C, pH 6 to 8, and 3 to 15 dGH.

Both plants are comfortable in freshwater, so salinity is not a meaningful obstacle.

Flow is workable if the layout gives Common Duckweed gentle, low-flow water and Congo Anubias moderate flow.

Both fit low light and no added CO2, so one lighting and CO2 plan can support the pair.

They naturally settle into different parts of the scape, which gives you more room to use each species for what it does best instead of forcing direct competition.

Common Duckweed reaches about 0.2 cm tall by 1 cm wide, while Congo Anubias reaches about 50 cm tall by 30 cm wide. Use those mature sizes for the layout, not the small nursery portions you bring home.

Shade is not the main concern here, which makes the layout easier to keep balanced over time.

Common Duckweed is typically free-floating with no substrate required and feeds mainly as a water column feeder. Congo Anubias is typically roots anchored, rhizome exposed with no substrate required and feeds mainly as a water column feeder. That difference can make the pairing easier to arrange than two plants fighting for the exact same root or attachment zone.

Mature size is not the main thing working against this pairing, so normal maintenance is usually enough to keep the scape readable.

Common Duckweed brings fast growth, high maintenance, and beginner difficulty. Congo Anubias brings slow growth, low maintenance, and beginner difficulty. If one grows much faster, trim that plant before it starts making the other look like the problem.

The main watch-out is that growth pace and maintenance rhythm are uneven, so the stronger grower can dominate if pruning slips.

The strongest reasons to try the mix are that they share a workable temperature window around 22 to 28 °C; and that their flow preferences sit close enough to tune one layout around both plants.

Use this pairing when you are willing to manage the scape, not when you want a plant-and-forget combination. Start with more spacing than you think you need, then adjust once both plants show their real growth pace.

The simple success test is whether both plants still look healthy after the faster grower has been trimmed several times. If one keeps declining after routine care, the layout is probably asking too much of it.