Green barbs breeding ?

Guppy10

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Hi, I have 2 green barbs intensely pecking each other on their mouths and being in tight formation but no damage done so are they mating or just arguing ?
I also have a Molly which when approached by a barb raises itself vertically, head up and seems to allow the ba rb to nip it, again no harm done then they return to normal. Can anyone explain this odd behaviour.
 

Byron

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It is stress on the part of the barbs because they do not have a sufficient number of their own species. Studies have shown that when shoaling fish are not in decent-sized groups it causes them stress, and the most common way of dealing with this frustration is increased aggression. Six is the usual number suggested for barbs, but a few more is always going to be better for the fish, and some species must have larger groups (Tiger Barbs for example, which are naturally aggressive). I am assuming "Green Barb" is actually the green variety of the Tiger Barb, Puntigrus tetrazona. This fish should have a group of no fewer than eight, with 10-12 much better, and requires a tank with minimum dimensions of 30 inches by 12 inches (75 cm by 30 cm) such as a basic 30g. With other species, the tank needs to be larger than this.

"No harm done" is a bit misleading. The mere fact the two fish are together is causing stress because they have chemical signals of communication, phermones and allomones, and these cause considerable stress even without actual physical interaction.
 
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Guppy10

Guppy10

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I mean no damage done to either fish so not too hard to understand. They are otherwise fine and looking superb so is there any factual matter to back up that they are stressed ? They all seem fine so is this your opinion or can you back up with data? I try not to reiterate others opinions as fact and go by my own experience. You have your opinion.
 

Byron

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I mean no damage done to either fish so not too hard to understand. They are otherwise fine and looking superb so is there any factual matter to back up that they are stressed ? They all seem fine so is this your opinion or can you back up with data? I try not to reiterate others opinions as fact and go by my own experience. You have your opinion.
It is not my opinion, it is scientific fact accepted by every ichthyologist and biologist. I do specifically recall one study that looked into this [there may well be others, I do not spend time looking for papers to support accepted science as that would get us no where] and the paper is free here:

 

seangee

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I agree. I have seen this type of behaviour time and time again in over 30 years of keeping fish, including in my own tanks before I knew better. Please remember that you came to this site looking for advice. You were given sound advice by one of our most respected members.

What you choose to do with this advice is entirely your own choice.
 
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