Aponogeton ulvaceus
Aponogeton ulvaceus
Also known asWavy-edged aponogeton · Betta bulb (trade) · Compact aponogeton
Water parameters
Light and nutrients
Substrate type: any. Propagation: bulb.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Inert sand (Pool filter sand) | neutral / inert | none |
| Inert gravel (Aquarium gravel) | neutral / inert | none |
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Dirted tank (mineralized topsoil) (DIY soil substrate) | slightly acidic | very high |
With fish
Origin and habitat
Endemic to western and central Madagascar, in slow streams, pools and lake margins. A tuberous member of the family Aponogetonaceae, it grows from a small cone-shaped tuber into a rosette of broad, thin, translucent leaves that are bright to pale green, turning reddish under intense light, and run well over 50 cm with strongly wavy, ruffled margins resembling sea lettuce, Ulva, which gives the species its name. A mature plant can carry forty or more leaves and is among the largest and most striking aquarium plants. Like other Aponogetons it grows from a bulb and rests periodically, dying back to the tuber before regrowing, though being from a warm tropical island its dormancy is less pronounced than in temperate species. It is sometimes sold loosely as a 'betta bulb' and confused in trade with the lace plant, A. madagascariensis, which is a different species.
Care notes
A showpiece for medium to large tanks with moderate to strong light, though it tolerates a wide range. Plant the tuber with its top half exposed; the long wavy leaves need room, and a mature plant can fill a 30 cm radius with flowing, translucent foliage that waves dramatically in filter current. It is a heavy root feeder, so root tabs are essential, and water-column dosing of nitrogen, phosphorus, potassium, iron and trace elements supports its fast growth; underfed, the new leaves come smaller and less ruffled. CO2 is not required but boosts vigour and leaf size. In good conditions it grows fast, a new leaf every couple of days, each potentially 30–50 cm long. Dormancy happens but is unpredictable: some plants run for years, others rest, and a dormant tuber left in the substrate usually regrows within a month or two, or can be lifted and stored in damp sand for about two months. Propagate by daughter bulbs that form beside the main tuber, or by seed, though the plant is not self-fertile and needs a second flowering plant to set seed. It has a reputation for vigorous growth then occasional decline, usually from a spent bulb or oncoming dormancy rather than death, so replenish root tabs and wait. Only dedicated herbivores damage the delicate leaves. It is an ornamental rosette, not a crop, so it is unsuited to media-bed aquaponics or hydroponics.