Bristlenose destroying my tank!!


Guru Class Expert
Feb 3, 2007
Dixon IL
A few weeks I got 3 bristlenose plecos with intentions to try breeding them. All was well at first and then one morning I woke up and noticed my ludwigia repens stems were turning brown and the plants dying. They are turning brown randomly and I am assuming it is from some kind of trauma to the stem.

I also had two large ozelot swords that have been demolished by these three. There is no question they ate these leaves as you can see the rasp marks up and down the leaves. I had been feeding them algae wafer with the occasional zucchini. Should I increase the veggies? All 3 are about 3.5" which is close to full grown. I am assuming I can get them to quit eating my swords by feeding them better but what is causing the trauma to the Repens? I am assuming it was just damage from them swimming as they are by far the biggest fish I have in the tank. You don't think they were rasping on those as well do you?


Plant Guru Team
Lifetime Member
Sep 23, 2007
South Florida
I agree the bristelnose are responsible for the sword damage. My single destroys any you put in there.

Feeding extra will help, but they love swords, IME.

Others have not had this issue.

The Rotala might need pruning. I have had this blackening of the stems before and I usually prune and trim, as the lower leaves/stems are not getting any light and the mass affects flow/current. Rotala can get pretty thick in there when it grows well.

Take some tops and plant about 1-1.5" apart. They grow back quickly.

I have this issue less since I dose EI...........

Good luck,

Darrell Ward

Junior Poster
Feb 17, 2005
Never again will I add Bristlenoses to my plant tanks containing swords. I put 2 in my 240 gal. that had a couple of 24" plus swords. In a matter of days they completely destroyed most of the leaves before I was able to catch them. It will likely take a good while for them to grow back to their original size.

Tom Barr

Staff member
Jan 23, 2005
I had them with swords without issues, they likely where hungry, perhaps got a taste for the plants etc.

Tom Barr


Guru Class Expert
Jun 26, 2008
Albany, California
I've had two BN Plecos in my 72 gal planted tank for almost a year. And with two swords and a load of other plants. Other than occasionally knocking a newly planted stem when they were rooting around like normal I've had no problems. It might be keeping them satiated. I do drop a few algae wafers or Hikari sinking tabs 1-2x a week and every 2 weeks or so cut a piece of english cucumber (this one does not cloud the water like zuch's or the regular "fat" cucumbers) and tie it to a small stone and sink it to the bottom. They find it in about 2 minutes. They LOVE it. It's almost gone in one day.