Bullying Female Lyretail Swordtail - Help Please!

[totally tropical]

I have 1 female lyretail swordtail amongst other fish, anyhow I recently introduced to my 300 litre tank young 4 koi swords (1 male and 3 females). I assumed that as the lyretail is a female there would be no problems.

She is constantly bullying all 4 koi swords especially the male and she is getting worse to the point where I am having to put her in a breeding net to give the others a breather! I have also seen her have a rare pec at my pearl gourami, the other having died recently and it may be that the lyretail is responsible.

It looks like I will have to get rid which is a shame as she is a beauty.

Any ideas on any of the above.

Many thanks.

 

[KittyKat]

Swordtails are quite aggressive, on average. The only way to even it out is get fish of her own size, so they keep themselves busy (males trying to mate, females trying to avoid males). Best ratio is 1:2-3 males per females.

 

[OldMan47]

Some swords can be very aggressive. Especially the highly developed ones, when the breeding program is not well enough monitored by the breeder. I find KitKat's statement a bit extreme but the point that you may need to remove the offending fish is valid. I would not try increasing the number of swords in your tank. You may have a late bloomer in your fish, a former sneaker male as it were, who is seeing the other male as a challenge and is ready to defend his territory. Late blooming male swords average quite a bit bigger and heavier than early bloomers and in many ways resemble a female. It can even take a year or more for the obvious sexual characteristics of a male sword to develop.