Resolving Guppy Aggression

Hello all,

So, I have a bloodthirsty guppy on my hands, and as I'm about to upgrade to a 29 gallon tank and move my fin babies, I wanted some advice to how more experienced fish keepers would proceed.

TL;DR Background: previously peaceful guppy now an absolute terror to the other males in the tank.

Full background: Last fall, I bought a ten gallon tank for my dorm. When I went to my LFS, they recommended guppies -- specifically, they suggested a trio of males to start out. I had doubts -- I knew they tended towards fin nipping if there weren't enough females to keep them busy. But I was assured that if these boys were never around females, they'd be fine. And they were!

Until I lost one of my guppies this summer. Tequila Sunrise had chronic constipation issues (even blanched peas were of no help) and his quality of life was getting worse and worse, so I euthanized him (and cried). Within days, my orange delta guppy was aggressively chasing and tormenting my turquoise guppy. My turquoise guppy has a large fancy tail, so despite being significantly larger than the delta, was constantly under assault. However, there was never any biting, just chasing that went beyond "play." My turquoise guppy would only come out of hiding from the plants at night when the delta was resting.

After a week, I went to my LFS for their advice. They said that the delta was essentially threatened and trying to be the "alpha" of the tank now that the numbers had shifted. They sold me another male guppy and said restoring the numbers back should fix the problem.

Spoiler: It did not. The first three days, it was peaceful. But this morning I woke up and my new guppy's tail fin was massacred. Both he and my turquoise guppy were hiding together from the delta, which chased them back into the plants when they tried to eat during their morning feeding. The delta is now extremely aggressive and attempted to bite both of the other males fins before I separated all three of them.

Potential Courses of Action

1. Buy females when I upgrade my tank, and potentially get a fish that will eat the guppy fry.
2. LFS suggestion: buy more males so the bullying is "spread out."

To be honest, I'm not trusting suggestion two with my recent experiences. I think it may have just been a fluke that my first trio weren't violent before, and now they need more than their own reflections to occupy them and some females would help curb this behavior. Any thoughts on how you would resolve this?

Thanks in advance for the advice!

 

I would add some females (enough for each male) or remove the little troublemaker. It reminds me of my bantam rooster who would go after a big black rooster three times his size just to try to be a little tough guy.

 

I would add some females (enough for each male) or remove the little troublemaker. It reminds me of my bantam rooster who would go after a big black rooster three times his size just to try to be a little tough guy.

Sounds like a good plan! My other two guppies still seem very stressed and defensive (though not at all aggressive to each other). Any ways to help them relax?

 

I keep a fraternity of 9 guppies and aggression is very minimal. I have them in a 20 gallon tank with plants and such. This helps reduce aggression by blocking line of sight and they like to explore a lot. Also, if you doall male I would say at least 5 because the more you have the less aggression (at least from my experience). Just in case you don't want a population explosion by adding females.

 

I keep a fraternity of 9 guppies and aggression is very minimal. I have them in a 20 gallon tank with plants and such. This helps reduce aggression by blocking line of sight and they like to explore a lot. Also, if you doall male I would say at least 5 because the more you have the less aggression (at least from my experience). Just in case you don't want a population explosion by adding females.

I just bought my new 20 gallon, so I think that will be my attempted solution! One of my friends used to breed guppies and suggested a similar set up, and chalked it up to there being too few boys in the house and perhaps not enough cover in the middle of the tank.