Anubias Plant Turning Black – Your 5-Step Rescue & Prevention Guide
That sinking feeling. You gaze into your beautiful aquarium, and your eyes land on your trusty Anubias—the one plant that’s supposed to be indestructible. But something’s wrong. Its deep green, waxy leaves are marred by ugly black patches. It’s a frustrating sight, and if you’re wondering what went wrong, you’re not alone.
Don’t worry. An anubias plant turning black is one of the most common issues aquarists face, and I promise you, it’s almost always fixable. This isn’t a sign you’ve failed; it’s just your aquarium sending you a signal that something is slightly out of balance.
In this guide, I’m going to walk you through everything, just like a friend looking over your shoulder. We’ll pinpoint the exact cause of the blackening—is it pesky algae or something more serious?—and I’ll give you a step-by-step plan to treat it. By the end, you’ll not only have a solution but also the knowledge to prevent it from ever happening again.
Ready to bring your Anubias back to its vibrant, green glory? Let’s dive in.
Is It Algae or Rot? The Critical First Step
Before you can fix the problem, you need to play detective. When an Anubias turns black, it’s almost always due to one of two culprits: a surface-level algae or a more serious internal issue called rhizome rot. Figuring out which one you’re dealing with is the most important step.
Identifying Black Brush Algae (BBA)
Black Brush Algae, or BBA, is the most frequent cause of blackening on Anubias. It’s a stubborn type of red algae (confusing, I know!) that looks like dark, fuzzy patches or short, beard-like tufts.
- Appearance: It looks like short, dark gray or black fuzz, often growing along the edges of the leaves. It feels coarse to the touch.
- The Test: BBA grows on the surface of the leaf. If you look closely, you can see the leaf underneath is still green. While tough, you can sometimes scrape it off with a fingernail. The leaf itself remains firm.
- Common Causes: The number one trigger for BBA is fluctuating or low CO2 levels. Other causes include excessive light intensity or duration, and an excess of organic waste in the water.
Identifying Anubias Rot (Rhizome Rot)
Anubias Rot is a much more serious condition. This isn’t something growing on the plant; it’s the plant itself decaying from the inside out. This is one of the most common problems with anubias plant turning black for beginners.
- Appearance: The black areas will look mushy and decayed. Leaves will turn yellow, then transparent, then black, and will detach from the rhizome with the slightest touch.
- The Test: Gently touch the rhizome (the thick, horizontal stem-like part the leaves grow from). If it feels soft, squishy, or falls apart, you have rhizome rot. There might also be a noticeable foul, decaying smell.
- The #1 Cause: The rhizome has been buried in the substrate (gravel or sand). The rhizome needs to be exposed to the open water to “breathe.” Burying it suffocates the plant and causes it to rot.
Once you’ve made your diagnosis, you can move on to the treatment. Let’s get that plant healthy again!
The Ultimate Anubias Plant Turning Black Guide: Treating the Problem
Okay, you’ve identified the enemy. Now it’s time to fight back. The treatment plan is completely different depending on whether you have algae or rot, so follow the steps for your specific situation. This is your complete anubias plant turning black guide for recovery.
How to Defeat Black Brush Algae on Anubias
Fighting BBA is a two-pronged attack: first, you remove the existing algae, and second, you fix the tank imbalance that allowed it to grow in the first place.
Manual Removal & Pruning: For lightly affected leaves, you can take the plant out during a water change and gently scrub the algae off with a soft toothbrush. For leaves that are completely covered, it’s better to just prune them off at the base of the stem with sharp aquascaping scissors. This allows the plant to direct its energy toward new, healthy growth.
The Pro-Level Spot Treatment: This is one of the best anubias plant turning black tips you’ll ever get. Get a small syringe or pipette and some liquid carbon (like Seachem Flourish Excel or API CO2 Booster). Turn off your aquarium filter and any powerheads to stop the water flow. Carefully squirt a small amount of the liquid carbon directly onto the BBA tufts. Let it sit for 5-10 minutes before turning your filter back on. Within a day or two, the BBA will turn pink or white and die, at which point your shrimp and snails will happily clean it up.
Address the Root Cause: This is the most crucial step for long-term success. Spot treating BBA is just a band-aid if you don’t fix the underlying issue.
- Stabilize CO2: If you use injected CO2, ensure it’s consistent. Use a drop checker and make sure your CO2 turns on an hour before your lights do.
- Reduce Lighting: Anubias are low-light plants. If your light is too intense or on for more than 8 hours a day, you’re rolling out the red carpet for algae. Reduce your photoperiod to 6-7 hours.
- Increase Maintenance: Up your water change schedule and be thorough with your gravel vacuuming to remove excess organic waste that fuels algae.
How to Save Your Anubias from Rhizome Rot
If you have rhizome rot, you need to act fast. It’s like performing surgery, but don’t be intimidated—it’s your plant’s best chance at survival.
Get the Plant Out: Carefully remove the entire Anubias from the aquarium and place it in a small bucket or on a towel. This prevents decaying matter from fouling your tank water.
Perform “Surgery”: Take a clean, sharp razor blade or pair of scissors. Carefully examine the rhizome and cut away every single piece that is soft, brown, or black. You need to be ruthless here. You must cut back until you only see firm, healthy, whitish-green tissue. Any rot left behind will continue to spread.
Replant It Correctly: This is where you ensure the rot never comes back. Do not bury the rhizome again. Instead, attach the healthy remaining piece of rhizome to a piece of driftwood or a rock. You can do this using:
- Super Glue Gel: Use a tiny dab of cyanoacrylate super glue gel (like Gorilla Glue Gel). It’s completely aquarium-safe once cured.
- Fishing Line or Cotton Thread: Tie the rhizome gently but firmly to the hardscape. Cotton thread will dissolve over time, by which point the plant’s roots will have anchored themselves.
By placing the rhizome in the open water column, you allow it to get the flow and light it needs to thrive, effectively eliminating the risk of rot.
Best Practices for Prevention: Keep Your Anubias Green for Good
You’ve treated the problem, and your plant is on the road to recovery. Fantastic! Now, let’s make sure you never have to deal with this again. Following this anubias plant turning black care guide will set you up for long-term success.
Master Your Lighting and Nutrients
Anubias are the kings of low-tech tanks for a reason: they don’t demand much. They are slow growers, which means they use light and nutrients very slowly. Giving them too much of either is a recipe for algae.
Aim for a low-to-medium light setting for about 6-8 hours per day. If you can’t dim your light, consider raising it higher above the tank or adding floating plants like Frogbit to diffuse the intensity. This simple change is one of the most effective anubias plant turning black best practices.
The Golden Rule: Never, Ever Bury the Rhizome
I know I’ve said it before, but it’s worth repeating because it’s the #1 mistake beginners make with Anubias. The rhizome is not a root. It’s a thick, horizontal stem that stores energy. Burying it in your substrate cuts off its access to oxygen and flowing water, causing it to suffocate and rot.
Always attach your Anubias to driftwood, rocks, or other decorations. The thin, stringy roots that grow down from the rhizome can go into the substrate, and that’s perfectly fine—they will anchor the plant and absorb some nutrients. But the rhizome itself must stay above the gravel or sand.
Maintain a Clean, Balanced Ecosystem
A clean tank is a healthy tank. Algae, including BBA, thrives on excess nutrients and organic waste from fish food, fish poop, and decaying plant matter. A stable, clean environment gives your plants the advantage over algae.
- Regular Water Changes: Perform consistent weekly water changes of 25-50% to remove dissolved organics and reset nutrient levels.
- Don’t Overfeed: Only feed your fish what they can consume in a minute or two. Excess food breaks down and becomes algae fuel.
- Enlist a Clean-Up Crew: Amano shrimp are BBA-eating machines, and Nerite snails are fantastic at cleaning surfaces. They are a great, eco-friendly anubias plant turning black prevention squad.
The Unexpected Benefits of a Plant Problem
It might sound strange to talk about the benefits of anubias plant turning black, but hear me out. Going through this process does more than just save a plant; it makes you a better, more observant aquarist.
By learning to diagnose and solve this issue, you’ve gained a deeper understanding of the delicate balance between light, CO2, and nutrients in your aquarium. You now know how to spot the early signs of an imbalance and how to correct them. This experience turns a frustrating problem into a valuable lesson, empowering you to create a more stable and thriving underwater ecosystem. A healthy Anubias is a cornerstone of a beautiful, sustainable aquarium.
Frequently Asked Questions About Anubias Turning Black
Can an Anubias leaf recover after turning black?
It depends on the cause. If the black is Black Brush Algae on the surface, the leaf underneath is likely fine once the algae is removed. However, if the leaf tissue itself has turned black and mushy from rot, it is dead and will not recover. It’s best to prune these dead leaves off to allow the plant to focus its energy on new, healthy growth.
Will my fish or shrimp eat the black stuff on my Anubias?
Some critters will help, but they’re not a magic bullet. Amano shrimp and true Siamese Algae Eaters are known to graze on BBA, especially when it’s young or dying after a spot treatment. However, they rarely eliminate a full-blown infestation on their own. No fish or shrimp will eat a rotting plant.
Is it safe to use super glue to attach my Anubias?
Yes, it is 100% safe, provided you use the right kind. You must use a super glue gel that is 100% cyanoacrylate. The gel formula is easier to work with and less runny. It becomes completely inert and waterproof the moment it cures, which happens almost instantly upon contact with water. It will not harm your fish or invertebrates.
How do I know if my Anubias is completely dead from rot?
If you’ve performed the “surgery” and found that the entire rhizome is soft, mushy, and falls apart in your hands with no firm, whitish-green sections remaining, then the plant is unfortunately beyond saving. A healthy rhizome should be very firm, similar to a raw potato or ginger root.
Your Path to a Thriving Anubias
Seeing your beloved Anubias struggle can be disheartening, but now you are armed with the knowledge and a clear action plan to turn things around. Remember the core lessons: identify whether it’s algae or rot, treat the immediate symptom, and then—most importantly—correct the underlying cause in your tank.
Every challenge in this hobby is an opportunity to learn and grow. By tackling this head-on, you’re not just saving a plant; you’re leveling up your skills as an aquarist. Be patient, be observant, and trust the process.
You’ve got this. Now go forth and grow something beautiful!
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