Part of the fun of choosing houseplants is finding one that you’ve not seen before. The fascinating and attractive Columnea nematanthus, or goldfish plant, is a flowering tropical that grows long, trailing stems, with gray, green, or purplish leaves. The plant gets its name from its bright yellow, red, or orange goldfish-shaped blooms. Although it can be a bit finicky about its environment, once you get the hang of the goldfish plant’s growing habits, you’ll become a true fan.
The most important thing to remember about goldfish plants is that they prefer temperatures between 65 and 75 degrees. If its surrounding environment is too cold, it will drop its leaves, then die. Tropical plants like Columnea are protected by the canopy of plants and trees in their native habitats, so they don’t thrive in temperatures that are too hot, either. High temperatures not only cause its lovely blooms to fade early but can also create an ideal environment for spider mites.
You may experience a few challenges if you’ve never grown a goldfish plant before, but the results will thrill you as soon as you see the first blooms appear. Goldfish plants need between 12 and 13 hours of bright — but not direct — sunlight every day. If you don’t have a spot in your home where the plant will receive sufficient light, try adding a grow light. Well-lit bathrooms and kitchens are great spots for these plants due to the added humidity levels.
Depending on your location, it’s possible to grow the goldfish plant outdoors. Avoid planting them in areas with direct sun. While they are humidity tolerant, you’ll need to monitor the amount of water and sun exposure they get. It’s easier to plant them in hanging baskets and containers when placing them outside. Move them inside during inclement weather or when the temperatures get too hot. One of the top varieties for hanging baskets is the Columnea Gloriosa, which grows long, reddish-orange flowers and vines that cascade luxuriously over the edges of the basket.
The goldfish plant prefers shallow pots and a coarse but light soil or growing medium. Though the leaves can appear almost succulent-like, the goldfish plant is not adept at retaining moisture. Your plant will thrive in equal amounts of sphagnum moss, vermiculite, and perlite. Or, try using two parts of a quality potting soil mixed with one part perlite. Don’t worry if your goldfish plant becomes rootbound — they prefer it. Repot the plant every two to three years, but only go up a single size.
To keep your goldfish plant thriving, mist it every day with room-temperature water to increase humidity levels. Never mist with cold water or you risk damaging the leaves. If the air is still dry despite your misting efforts, try setting up a humidifier in the room. Water the plant thoroughly from spring through fall and less frequently during the winter. You’ll know it’s time to water when the top two inches of soil have dried.
There’s nothing quite like seeing a goldfish plant in full bloom for the first time. Its brightly colored, tubular flowers resemble a school of goldfish. These plants bloom in spring and summer, but some home gardeners report year-round blossoms for indoor plants. The wide range of available flower and foliage options is part of the appeal.
Use a fish emulsion fertilizer, which is fast-acting and organic, to boost flower production during the goldfish plant’s blooming season. This fertilizer is rich in potassium, nitrogen, and phosphorus, with trace amounts of calcium, magnesium, and other elements. A half-dose of high-phosphorus fertilizer, like a 10-30-10 blend, every two weeks works well, too.
As with most plants, specific pests may seek a home on the goldfish plant. Check your plant regularly for signs of aphids, spider mites, and scale bugs, and use insecticidal soap to get rid of them. These plants are also prone to fungal leaf spots and botrytis mold. Mosaic viruses are common, causing yellow, white, or green spots or streaks on the plant’s leaves and stunting growth. Remove infected leaves and dispose of them.
Legginess is one of the top complaints about this plant. Usually, excessive length indicates that the plant isn’t getting enough light. Pinch or trim the tips to encourage a bushier plant with more blooms.
Want more goldfish plants? Simply propagate a new Columnea by cutting off a two- to three-inch stem tip that doesn’t have flower buds. Dip the cut end in rooting hormone before planting and place in a bright area. You’ll soon have a new plant from your cutting.
Columnea is an epiphyte, which is a type of plant that grows on other plants, or in some cases, a power pole, fence, or building. Epiphytes often perch on the top of trees in their native tropical habitats. They obtain nutrients from the air, dust, water, and debris around them, not from their roots or the plant that they’re growing on. Goldfish plants are cousins to the African violet.