Rainbow cichlids

[Waterstrider]

I have a group of rainbow care cichlids. Today one flashed or rubbed against the sand and was immediately chased /attacked by a bn pleco that was nearby but not close enough that the cichlid was going after it (and it never has). Thoughts?
90 g tank, med- hard water, no eggs in tank

 

[kribensis12]

I'm not entirely sure of your question - but yes, bristle nose can be aggressive (any fish can be if they feel threatened). Normally they are not, my guess is that the bristle nose felt threatened.

 

[Waterstrider]

I'm not entirely sure of your question - but yes, bristle nose can be aggressive (any fish can be if they feel threatened). Normally they are not, my guess is that the bristle nose felt threatened.

I’m just not sure why; they’ve lived together for years. Just wondering where this is coming from and maybe this could be something the cichlids are doing. I so cannot sex these guys. Bn is male, the firemouth male, rainbows no idea. Wondering if there might be a breeding thing

 

[kribensis12]

Fish are not domesticated - they do not have learned behaviors. You could have a smoothly running tank for 2 years and wake up one day to a bunch of dead fish because the fire mouth snapped etc. Not to frighten you, it's just the way it is.

It's likely the Bristlenose felt threatened. That does not mean they will continue to fight - most likely a one-off thing as bristle nose usually keep to themselves.

 

[Waterstrider]

Anybody have any sexing methods for rainbow?