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Your fishbone cactus is skinny because it’s not getting enough light, and that’s the most common reason by far.
This unique cactus, also known as Epiphyllum anguliger or the ric rac cactus, naturally grows in the wild as an epiphyte under the canopy of trees, where it receives bright but filtered sunlight.
When you bring it indoors, your fishbone cactus can easily end up in a spot that’s just too dim for its liking.
A skinny fishbone cactus is your plant’s way of stretching out and reaching for more light, and it’s a sign you need to adjust its environment.
In this post, we’ll dig into every reason your fishbone cactus is skinny, how to fix it, and what you can do to help it grow those lovely wide, zigzag stems.
Let’s get that fishbone cactus looking lush and full.
Why Your Fishbone Cactus Is Skinny
Your fishbone cactus is skinny primarily because of insufficient light, but there are a few other culprits that can cause the same spindly look.
Understanding exactly why your fishbone cactus is skinny will help you correct the issue quickly.
1. Not Enough Bright, Indirect Light
The number one reason your fishbone cactus is skinny is light deprivation.
These jungle cacti crave bright, indirect sunlight for most of the day, and without it, they produce long, narrow, and weak growth.
You see, the wide, flat segments of a healthy fishbone cactus are essentially solar panels, and when light is scarce, the plant stops investing energy in making them wide.
Instead, your fishbone cactus is skinny because it’s putting all its energy into growing longer and thinner stems to escape the shade.
A good rule of thumb: if your fishbone cactus is more than a few feet from a bright window, it’s probably not getting enough light.
Try placing it in an east-facing window for morning sun, or a north-facing windowsill that gets consistent, gentle brightness.
If you can’t provide natural light, a grow light works wonders.
2. Overwatering or Poor Drainage
While you might think a skinny fishbone cactus needs more water, overwatering can actually cause weak, skinny growth.
This cactus has shallow, delicate roots that are prone to rot if they sit in soggy soil.
When the roots are damaged, they can’t absorb nutrients or water properly, and the plant responds by producing thin, stunted stems.
Your fishbone cactus is skinny because its root system is struggling to support healthy foliage.
Always let the top inch or two of soil dry out completely before watering again.
And make sure the pot has drainage holes so excess water can escape.
A well-draining mix, like a blend of potting soil, perlite, and orchid bark, is ideal for this epiphytic plant.
3. Lack of Nutrients
Your fishbone cactus is skinny, and it might be because it’s hungry.
Fertilizer provides essential nutrients for cell division and stem growth.
If you’ve never fed your fishbone cactus, or if it’s been in the same soil for years, the potting mix is likely depleted.
Without nitrogen, phosphorus, and potassium, your fishbone cactus can’t produce the thick, robust segments it’s known for.
Feed your fishbone cactus with a balanced liquid fertilizer diluted to half strength once a month during the growing season, which is spring through summer.
Avoid fertilizing in the winter when the plant is resting.
4. Temperature Stress
Your fishbone cactus is skinny because it might be too hot or too cold.
These plants prefer stable temperatures between 60°F and 75°F.
If your fishbone cactus is exposed to sudden drafts, blasts from heating vents, or cold windows in winter, it gets stressed.
Stressed plants often shed their wide segments and push out skinny, unbalanced growth as a survival response.
Keep your fishbone cactus away from air conditioners and radiators.
And if it’s near a cold window, move it a few inches back.
How to Fix a Skinny Fishbone Cactus
Fixing a skinny fishbone cactus is entirely doable, and your plant will thank you for the extra care.
Once you understand why your fishbone cactus is skinny, you can take steps to encourage broader, healthier stems.
1. Move It to a Brighter Location
Start by relocating your fishbone cactus to a spot with more bright, indirect light.
A sheer curtain over a south or west window will give it that dappled jungle feel it loves.
If you’re using a grow light, keep it on for 10-12 hours a day, positioned about 12 inches above the plant.
Within a few weeks, you should notice the new growth coming in wider and more defined.
2. Prune the Skinny Stems
It helps to prune away the thinnest, most stretched-out stems.
Your fishbone cactus is skinny and those weak segments won’t plump up later.
Use clean, sharp scissors to cut these stems back to the base or to a node.
This redirects the plant’s energy into producing fresh, healthy stems from the roots.
You can even propagate the cuttings in water or moist soil to start new plants.
3. Repot with Fresh Soil
If your fishbone cactus is skinny due to poor roots, repotting is a great fix.
Gently remove the plant from its pot and inspect the roots for any black, mushy rot, then trim those away.
Repot in a slightly larger container with fresh, airy soil.
This gives your fishbone cactus a clean slate with proper drainage and nutrients.
4. Be Patient with New Growth
After making changes, don’t expect overnight results.
A skinny fishbone cactus takes a few growing seasons to bounce back fully.
The older skinny stems will always stay thin, but the new segments will be noticeably wider and more robust.
Keep your watering and feeding routine consistent, and the plant will reward you.
So, Why Is My Fishbone Cactus Skinny?
Your fishbone cactus is skinny because it’s likely not getting enough bright indirect light, and that’s the core reason for that spindly, stretched appearance.
It might also be due to overwatering, a lack of nutrients, or temperature stress, but light is almost always the main culprit.
The good news is that your fishbone cactus can recover with simple adjustments to its care routine.
Move it to a brighter spot, feed it regularly, watch your watering habits, and prune away the weak growth.
With time and care, your fishbone cactus will grow those beautiful, wide zigzag stems again and look full and healthy.
You’ve got this.