Nematanthus ‘Goldfish Plant’ Koi Red 4”

Nematanthus gregarius Koi ‘Red’ | Red Koi Goldfish Plant

Deep red fish-shaped flowers against glossy green foliage give Red Koi a richer, darker look than the familiar orange-flowering Goldfish Plant. The flowers sit along trailing stems and have the same inflated shape that gives this entire group its common name, but the deeper red coloring makes this selection especially striking in bloom. Koi ‘Red’ is grown as a selected form of Nematanthus gregarius, a tropical epiphytic species native to southeastern Brazil.

Red Koi develops branching stems that become increasingly trailing as they grow, making it a natural choice for a hanging basket or elevated pot. Pruning longer stems can encourage additional branching and create more growing tips rather than leaving the plant with only a few long vines. Because flowers develop along established growth, building a healthy, well-branched plant gives it more opportunities to bloom.

For natural light indoors, place it directly in an east-facing window or approximately 1–2 feet from a south-facing window. Aim for approximately 800–1,500 foot-candles at the leaves. Foot-candles simply tell you how much light is actually reaching your plant. Good usable light supports compact growth and flowering. The red flower color belongs to this selection, so stronger light is not what creates the red. Watch the new stems instead. Increasing distance between leaves, thinner growth or a plant that continually grows without developing buds can be reasons to evaluate the amount of usable light it is receiving.

Under a grow light, use a full-spectrum 5000–6500K fixture approximately 8–12 inches above the canopy, aiming for 800–1,500 foot-candles at the leaves. Keep the actively growing portion of the plant within the fixture’s coverage as the stems lengthen. A hanging plant can have plenty of light at the top of the pot while its active growing tips have moved well beyond the strongest part of the fixture.

Water when your plant needs watered. Allow it to use a good portion of the available moisture before watering thoroughly again, but avoid repeatedly taking the plant to an extreme dry. Its slightly fleshy leaves provide some moisture storage, while its epiphytic roots still appreciate a root zone that combines available moisture with plenty of air. A loose mix of potting soil or coco coir, chunky orchid bark and coarse perlite or pumice works well for that balance.

Pay attention to the newest stems, leaves and developing buds. Firm glossy foliage and compact new growth are good signs that the plant is actively growing. If leaves begin dropping while the pot remains wet for a long time, look at the roots and how quickly the plant is actually using water. If growth becomes increasingly stretched, look at usable light. A pause between flowering cycles can be completely normal, so use the condition of the whole plant rather than the presence or absence of flowers on a particular day to decide how it is doing.

Success looks like a full, branching plant with healthy trailing stems, glossy foliage and repeated flushes of those distinctive deep red flowers. Keep your attention on the growth happening between flowering cycles too. When Red Koi is producing strong stems and leaves, using water consistently and continuing to build new growth, it has the foundation it needs for the next round of flowers.