Male vs female aggression


I got this pair of bristlenose plecos that are about full grown for about 6 months now for breeding purposes. Although they didn’t breed the pair seemed to go along ok mostly avoiding each. But just today I did the first water change in 2 weeks and moved around some plants making more of an open space and with the first feeding the both have been going at it. The male seems to be the aggressor fighting when the ever the female comes close. I’m starting to have some doubts on whether the female may be a sneaker male sense it does a few bristles although small. My question is how can I tell for sure it’s a female and why did they start fighting.



Some females have small bristles around their mouth, but not large ones on their heads like the males do. Since the aggression started at feeding time and you say they are full grown now, is there a possibility they aren't getting enough to eat? Are there enough hides for each of them? Just throwing out some ideas, because you are correct in saying that bristlenose are not generally aggressive except between males.


A picture would help us?
The females whiskers will only be on the lower lip . Nothing at all on the rest of the face.

If you have a couple of specially shaped pleco caves and you have feed them frozen or live foods she would have eggs and they would breed.

I have found after conditionin with live and frozen food before putting BN that are 3 or more inches together they start to breed in 3 days . Basically fry in around a week. The female is removed as soon as the fry are seen for fear of them breeding again .

If it’s been six months something is wrong maybe?
I assume you have multiple tanks to raise as many fry as you want? Separate the two for a few weeks of extra protein meals. Particularly the female. The male does not eat for 6 or so days and has his tail moving continuously so feeding him a special diet would not be a waste ?

To answer your question.
Females whiskers are only on the lower lip.
The aggression I have seen from males to males is often at meal time. Are you feeding zucchini and large protein rich pleco pellets. Maybe some frozen or live worms a couple of times a week?

Edit to add.
How big are they ? If they are 6 inches they might be past their best?


The male is about 4 and half inches and the female seems to be little smaller. I have suspected that I may not be feeding enough and plan on increasing it along with water changes. I do have a 10 gallon to raise the fry although I’m planning on also getting second 20 gallon long.
I don’t have special pleco caves but I do have two terracotta watering spikes. I think the main problem may just come down I’m not giving them enough protein sense their diet mostly consistents of cucumber, and repashy super green. I think may start giving some repashy grub pie as well as dried tubifex worms sense I have these already, and eventuallly get my hands on some frozen foods


Could it be they are hungry ?


I’m not sure, I always check their stomach to Make sure they’re not sinking and I feed them every two days.
There is some bristles on her face but they’re tiny some I’m not sure


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Male .
Smaller not the dominant fish in the tank but probably a male.
Females can have big bristles or small but not on the face like that only on the lower lip , I believe?


My BNs were obviously male and female, but your question got me wondering. Some guy on you tube had this to say:

FEMALE: Bristles on lip only
Head is fatter than male's in proportion to body
Abdomen is fatter than male's in proportion to body
Nose is hard to the touch. Male's is soft.
Nose is more rounded than male's


Well with the recent fighting as well as the description it’s probably safe to assume it’s a male. Thanks for all the help

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