Male guppy getting bullied.

I have a 20 gallon tank with around 18 guppies in it. (3 of which are the smaller native guppies 1 male, 2 female.) They’ve all been bred in the tank (numbers are kept down by rummy nose tetras). My male to female ratio is a bit off, 6 males to 12 females, but the tank had been very calm so I didn’t feel the need to buy new females. (Normally I’d like it at 1 male to three female.)

But one of my female guppies has gotten insanely aggressive over the last few weeks.
She’s attacking all the red males in the tank. The black, orange and native males are fine… The red males are all tattered.
I thought it was the red males fighting amongst themselves… So I spent some time watching the tank. It’s the one female doing all the damage. She’s one of the older fish in the tank (she’s bigger than all the boys, and all but one of the girls), and is the best breeders in the tank. She’s always pregnant, and I’m pretty sure half the males are her off spring.
Until recently she’s been just a normal guppy. She’d get a bit cranky when she was really heavy with fry… But she’d always been pretty mellow.

The last two weeks she’s focused her attention on one male guppy. The poor little guy’s tail is shredded. He’ll go try to go into hiding, but she hunts him down, chases him out, and attacks him again. I saw her grab onto the poor little guy’s tail and pull him across the tank this morning, I’ve kept guppies for nearly 7 years and I’ve never seen anything like it.

Any idea what could have sparked this rampage?
A lot of the information I’ve read suggests boosting the amount of females in the tank to re-establish the social order… But I’m a bit hesitant to try it. If it fails it seems like I’ll be getting new fish just to get them beaten up.

Any suggestions about how to calm her back down? Or is it time to put her in solitary confinement?

 

stick her in with a betta for a few days?

Other than that I'm sorry to say I don't have a good answer.

Welcome to fish lore also!

 

Lol, I like the idea of the beta. A big, red beta, lol.
My money would be on the guppy though, she's a pyscho.

Thanks for the welcome

 

sorry I couldn't be of more help. I have a tank of all males that are doing quite fine, so can't say much for the women of the bunch.

 

I kept all males for years without any problems.... Except blue ones. Every blue male I had ended up dead for no apparent reason.
I asked at my local aquarium, and their answer was an outstandingly helpful, "yeah... Blue ones do that a lot."

I've had a air bit of male on male bickering in my tank once I started adding females, but that's always been solved by adding more girls to the mix.

I was thinking about it, and this fish is around three years old. So she'd have had upwards of 15 pregnancys, hundreds of babies (most of which she ate, but still), and is currently being harrased by boys that she probably gave birth to some time last year... I'd probably go crazy and start attacking people too, .
My mum also suggested that she's going through fishie menopause and that I should drop some of her hormone replacement tablets into my tank for her...

 

I kept all males for years without any problems.... Except blue ones. Every blue male I had ended up dead for no apparent reason.
I asked at my local aquarium, and their answer was an outstandingly helpful, "yeah... Blue ones do that a lot."

I've had a air bit of male on male bickering in my tank once I started adding females, but that's always been solved by adding more girls to the mix.

I was thinking about it, and this fish is around three years old. So she'd have had upwards of 15 pregnancys, hundreds of babies (most of which she ate, but still), and is currently being harrased by boys that she probably gave birth to some time last year... I'd probably go crazy and start attacking people too, .
My mum also suggested that she's going through fishie menopause and that I should drop some of her hormone replacement tablets into my tank for her...

Thank you for that good laugh this morning!

Thou I was actually going to go more into the canabalistic tendencies route and discus hanable lecter lol

Either that or maybe being a canibal for so long she just has a thing for eating men? I dunno. Could always try to separate the females and do a hormone replacement theory but then that's just going to take WAY to much work to figure out the proper dosing for fish vs humans and then how to appropriately dose multiple individuals of different size and age.

 

Thank you for that good laugh this morning!

Thou I was actually going to go more into the canabalistic tendencies route and discus hanable lecter lol

Either that or maybe being a canibal for so long she just has a thing for eating men? I dunno. Could always try to separate the females and do a hormone replacement theory but then that's just going to take WAY to much work to figure out the proper dosing for fish vs humans and then how to appropriately dose multiple individuals of different size and age.

She's close to hitting the point of being to fat to chase things... She's a fair way off dropping her fry, so hopefully the "to fat to move" stage will give the tank a bit of respite.

She attacked my bristle nosed cat fish (Mr Sucky ) last night, and now he's got a chunk missing out of his tail too.

I gave them a massive feed last night of peas and brine shrimp, and that kept her busy for a while, and she seems a bit more passive today. I'm thinking I'll just throw food at the problem until it goes away, lol.

 

well it is one solution to it. Might also just be as you said a hormonal thing and calm down after the birth.

 

Well she still hasn't popped out the fry (poor thing is HUGE) but my aquarium light blew it's bulb, and due to a stupid amount of trouble getting one, my tank has been dark for 3 days. (Will be until next week at this week, not a happy camper.)

While this lack of light is probably going to kill off my plants, it seems to have settled the fish. My tetras seemed to have slept for most of the 3 days (starting to adjust now) and the guppies are just pottering around, nice and calm.
The boy getting bullied even has a bit of healing happening in his tail.

So, the problem seems to have been solved. (Until I put the light back on and they all loose their minds, lol.)