so there are some plecos that are pretty territorial...

wondering if your experience shows, they are only territorial to other plecos, or will they bully Cory's & or Oto's ( loaches, and generally bottom dwellers ) as well ( in general )

I bred Bristle Noses a long time. So this experience is from a species specific tank.

They are very territorial especially towards other plecs, the male will drive off everything in sight after spawning even females of the same genus. The alpha male will try to drive everything off the tank.

They are violent and conning pokers and nippers. With time I understood that pre-made caves does not work. You need to install slates on legs so they don't get flat on the bottom and have a good space between them and the bottom. Then fill it all with sand to the level of the slates...

This way they can dig their own caves and hideouts. And this really was a game changer towards aggression between males, a good global harmony and lots of happy babies.

Some species will take runs at any other bottom dwellers. Others will allow them into their caves. Now, I wish I could contribute which does what, but they are all fish I just haven't gotten into. I've watched them at friends', since I seem to know a lot of Loracarid keepers.

MaloK said:

I bred Bristle Noses a long time. So this experience is from a species specific tank.

They are very territorial especially towards other plecs, the male will drive off everything in sight after spawning even females of the same genus. The alpha male will try to drive everything off the tank.

They are violent and conning pokers and nippers. With time I understood that pre-made caves does not work. You need to install slates on legs so they don't get flat on the bottom and have a good space between them and the bottom. Then fill it all with sand to the level of the slates...

This way they can dig their own caves and hideouts. And this really was a game changer towards aggression between males, a good global harmony and lots of happy babies.

Click to expand...

Breeding fish in general are aggressive so no surprise your alpha was driving away anything and everything.


Most of the plecos I have had pay zero attention to the other fish. There can be some territorial assertiveness or maybe an occasional brush back over some food but for the most part everyone coexists well. Aggression I have witnessed is towards other plecos that look similar or same size wise. Generally speaking though most do fine in community settings with enough room for all inhabitants.

I have kept Ancistrus, hypancistrus, baryancistrus, panaque, hemiancistrus and a few others. If they have caves or crevices they can fit into, a place to call their own they do very well. I've had a few that have been a bit aggressive towards other fish in the past for whatever reason but it's never been for a prolonged period of time. My golden nugget (L018) and watermelon pleco (L330) will actively chase fish away from their claims in the tank. This is the only L018 I have ever had that has exhibited these types of behaviors as I've had 5 or 6 others that have not.

As with a lot of other fish I believe it's all on a fish by fish basis with plecos and generally speaking they're tolerant/friendly with community fish. As long as they're not breeding and kept in the right conditions as defined by space and hiding places they are a great addition to most aquariums. There are some beautiful specimens that I just love to look at like the black and whites. L046, L173, L236SW I own and breed. L136Cs are absolutely gorgeous and the holy grail L250s are pretty badass too. Good luck getting your hands on 250s though..

The black and whites can be kept in community aquariums but it's a thin line. They are slow feeders and won't come out to feed when you're in their presence for the most part. They will get outcompeted by all the other fish and can starve to death. I have seen some beautiful community setups where fishkeepers have had success but for the price of one fish i personally couldnt do it. Most people keep them in species specific settings because of this

L250


L136c

Most vegetarian fishes are territorial to some degree. This is because they are defending their patch of algae (their food source). Some fish like rainbow sharks, redtail sharks and black sharks are highly territorial towards any fish in their territory. Whereas other algae eating fishes like Whiptail catfish, Farlowella sp and Peckoltias don't really care if other fish swim around their algae as long as they don't eat the algae immediately around the fish.

This behaviour can also vary depending on how much food is in the tank. If there is lots of food, they are generally less aggressive compared to if there is no food in the tank.