Help to Identify Black plaque on plants - The Planted Tank Forum
  • 1 Post By monkeyruler90
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 06-26-2020, 08:10 PM Thread Starter
PTrader: (0/0%)
Join Date: Dec 2019
Posts: 4
Help to Identify Black plaque on plants

I have Aqueon 65 gal tank, 48"Wx 12"x 24" deep. It has natural gravel for substrate. I have had tank set up going on 3 years. It is a community tank of asst. tropical fish. I have attempted to grow a planted tank for a little over 2 years. Started with stock hood with LED strip and some Anubas and Swords, they grew alright at first then over time stopped growing then died back. The Anubas never have completely died, new growth comes out constantly just to have some type of black cover the tops of the leaves, then holes in the leaves till they die and fall off. I do not believe this is BBA as it has no hair type growth and feels like a hard scale to the touch. This also gets on all of the plants. See pictures. I have done so much reading here and other articles, and talked to LFS employees who gave multiple advice options, tested water for many problems they suspected and found no real issues. I have tried so many different approaches that honestly I am confused where I am at now.

Currently I have a Finnex 24/7 Planted 48 light, have had it for more than a year and have tried different lighting levels, intervals, and color mixes. At this time the remote has stopped working, so I am stuck at current settings. Before I replace it, I was hoping to get to the bottom of this and buy the proper lighting.
I am not interested in CO2 at this time, as not being able to grow even low light plants properly, I don't want to complicate things further. I have tried the whole regimen of Seachem liquid products, ( Flourish, Iron, Potassium, etc.) Tried Thrive for 1 bottle, then read it was for a heavily planted tank. Now I am using Thrive C, 2 pumps per week, and Flourish Excel dosing 2 times a week.
Ammonia, Ph, Nitrates, Nitrates always test good. Do about a 30% water change every 2 weeks. Fish very healthy. The only Algae issues I have is the green spot type on glass, has to be clean off every 4 -5 days.
I believe if I could find the cause of this black plaque that kills the plant leaves I may be on my way to success, but I have had issue with it for over 1.5 years. I have prunes, tried peroxide baths, it won't run off. The fact that is only on the top of the leaves I was thinking too much light, but having a 24" deep tank, my reading says that I need very bright light.

Any questions that I can answer, I will try. Any suggestions are welcome. Some of the reading has said that a deep aquarium need so bright light that CO2 is needed. Other have been successful without it.

Thanks for taking the time to read this post.
Attached Thumbnails
Click image for larger version

Name:	2020-06-26 10.41.28.jpg
Views:	19
Size:	430.0 KB
ID:	900279  

Click image for larger version

Name:	2020-06-26 10.41.54.jpg
Views:	21
Size:	421.6 KB
ID:	900281  

Click image for larger version

Name:	2020-06-26 10.42.04.jpg
Views:	21
Size:	395.8 KB
ID:	900283  

Terrgi is offline  
Sponsored Links
post #2 of 7 (permalink) Old 06-26-2020, 09:16 PM
Wannabe Guru
monkeyruler90's Avatar
PTrader: (72/100%)
Join Date: Apr 2008
Location: San Diego, Ca
Posts: 1,831
Send a message via AIM to monkeyruler90
interesting, how long are the lights on for? maybe cutting down the light time can help.
Do you have any algae eaters like ottos snails or shrimp? I do see tetras so hoping this is a community tank where these can fit in.
It's a good sign that the plants are growing new leaves but bad that they're being overcome by this.

is the black stuff easy to scrape off the leaves or it stays on?

No need to get CO2 or keep fertilizing. seems you have all that's necessary but just need to control the throttle that powers the plants/algae which should be the light intensity or time.
Terrgi likes this.

Fluval pimp #4 aka PIMP master!


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
monkeyruler90 is offline  
post #3 of 7 (permalink) Old 06-27-2020, 02:05 PM Thread Starter
PTrader: (0/0%)
Join Date: Dec 2019
Posts: 4
I have several Nerite snails, 1 Bristlenose Pleco, 2 Siamese algae eaters for cleanup routines. The light is on at this time for 9 hours per day. Started this about a month ago. Prior to that had it on from 10 AM - 2PM, then on at 5PM to 8 PM. Doesn't seem to have changed anything between 2 settings. The black does not rub off, is kinda like a scale. Not slimy, more rough. Peroxide or White vinegar does not affect it..
I forgot to mention in original post that I have to run UV light constantly. If I don't after about 2 1/2 weeks, water starts getting milky, then worsens until it is pea soup. After I start the UV light, water clears in about 3 days.
Terrgi is offline  
post #4 of 7 (permalink) Old 06-27-2020, 07:58 PM
Algae Grower
Preeths's Avatar
PTrader: (0/0%)
Join Date: Jan 2008
Location: Bangalore, India
Posts: 132
If its on Anubias and other plants that can be moved easily, the simpler solution would be to wash them under gentle running water and rubbing away the black algae gently. this will reduce the amount of algae in the tank. Next, Reducing the lights and dosing Glutaraldehyde usually keeps this in check.

Preeths is offline  
post #5 of 7 (permalink) Old 06-27-2020, 08:06 PM Thread Starter
PTrader: (0/0%)
Join Date: Dec 2019
Posts: 4
It doesn't rub off. Actually I have pruned all the leafs with black off on Anuba and Swords. New growth come out after awhile then black appears on them again. Is Glutaraldehyde the Excel? If so I add it twice a week. Thanks
Terrgi is offline  
post #6 of 7 (permalink) Old 07-04-2020, 06:49 PM Thread Starter
PTrader: (0/0%)
Join Date: Dec 2019
Posts: 4
Terrgi is offline  
post #7 of 7 (permalink) Old 07-04-2020, 08:26 PM
Algae Grower
PTrader: (0/0%)
Join Date: May 2020
Posts: 66
The black plaque appears to be some kind of red algae (BBA is one, but it comes in other forms too).

My first concern is that you said you get a bacterial bloom when you shut off the UV sterilizer. I’d guess that your tank is out of balance somewhere, because something needs to be feeding the heterotrophic bacteria.

Your choice of plants is tricky if you’re dosing ferts and have a bright light. They’re slow growing plants, so they won’t consume your nutrients quickly, and they tend to grow algae on the leaves. It would be better to put them in shade or drop your light level down drastically.

I’d start by trying to get your tank balanced out first, then deal with the red algae second. Unfortunately there isn’t really a magic bullet for eliminating it, but a balanced tank is the first step to controlling it.

Edit: scroll down this page to the BBA section for a photo of a plant that looks similar to your problem:
fermentedfunk is offline  


Quick Reply

Register Now

In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome