Male guppies fight for a few different reasons. The most likely scenario is you have more male guppies than female guppies. And the males are fighting for the attention of the lone female guppy.
There are other reasons guppies fight, but it’s almost always because of a lack of females in the tank. We will cover all the reasons that guppies fight in this article, how to know if your guppies are fighting, and offer some advice to stop the fighting.
How to Know if Guppies are Fighting
You can tell if your guppies are fighting by their damaged fins. If a male guppy is missing chunks from its beautiful fins, then it’s because another fish took a bite from its fins. That other fish is either a guppy or a fish in your tank that eats guppies.
It’s normally a fight with another guppy, though.
Of course, you can also tell if your guppies are fighting by observing them. Do they chase each other around the tank?
They aren’t wasting all that energy for fun. That’s the guppy version of a fist fight.
You will often notice that one or two guppies will aggressively chase around the other males in the tank. Those are the alpha males attempting to kill the competition.
3 Reasons Why Guppies Fight
It’s easy enough to know if your guppies are fighting, but why do guppies fight?
Guppies usually fight for mating rights to the female. The meanest, most aggressive guppy tends to get the female, so it’s an evolutionary thing.
That said, mating rights aren’t the only reason that male guppies fight. This section will cover some of the other reasons.
High Male to Female Ratio
Male guppies will fight each other over mating with a female. This becomes a much bigger problem when there is a high male to female ratio.
Unfortunately, this is also the best way to keep the guppy population in check – 1 or 2 females and 7+ males.
Male guppies also look better with their fancy tails, so many beginners add more males to their tank than females.
You can do this – I did this in my tank. Just expect a lot of fighting between the males and damaged tails with a such a high male to female ratio.
A small guppy population leads to more fighting. This sounds counterintuitive, but it’s the case because less males means more fighting for access to the lone female.
A larger population means that the guppies establish a sort of pecking order with different females for different males, which results in less fights.
You’ll still have fights with a large population, but you will have much less fights.
Not Enough Space
Finally, not all fights between guppies are over mating. Guppies sometimes fight over territory in smaller tanks despite being a non-territorial fish.
For instance, if you have a large amount of guppies in a small tank, then you will have a lot of fights over top water column territory. A smaller tank also means that weaker fish will have less areas to hide to avoid fights.
How to Stop Guppies from Fighting
There are a few ways to reduce the amount of fighting in your fish tank. As you might have guessed, the best way is to either add more females or only have one male in the tank.
There are more strategies than changing the population, though.
Add More Females
The easiest way to reduce the amount of fights in your tank is to simply add more females to the tank. A natural pecking order will form with the alpha male guppy going after the most desirable female guppy.
This should result in him fighting less. And since he’s almost always the one starting all the fights, the amount of fights and damaged fins will go way down.
I recommend a 3:1 female to male ratio to avoid the fighting problem. The obvious downside to this ratio is that you will have a lot of guppy fry to manage because female guppies give birth to ~30 fry every 24-30 days.
That could become an even bigger problem than some minor fights.
On the fun side, it does give you an excuse to buy fish that eat guppy fry.
Only Have Males
Male fancy guppies are the small ones with the large, flowing, colorful tails. The females are larger with not much color to them.
Most people prefer the males for their colors, so you can easily have a tank of only males in your tank.
This means no fry to manage, less fights, and prettier fish in your tank.
It’s my recommended option.
Add Floating Plants
Do you have floating plants in your tank?
If not, then you should consider adding some floating plants to cut back on guppies fighting. These plants will allow guppies to hide out where they spend most of their time – the top of the water column – and avoid fighting with the alpha male.
Floating plants also add character to your fish tank and keep the water clear. There is no reason not to add easy floating plants such as wisteria or Java moss (it can be floated).
Get a Bigger Tank
If you have a smaller tank (10 gallons or less) and have guppy fighting problems, then that is likely because your tank is too small and they’re fighting over space.
As mentioned earlier, a larger tank will reduce the fights because the weaker fish can find areas to hide.
The problem with a larger tank?
The guppies will expand to the Malthusian limit of the larger tank. Believe me, I tried that in a guppy-only tank and a Malthusian catastrophe occurred in the form of an ick outbreak that wiped out 70% of the tank.
That covers it for why your guppies are fighting. Your guppies are simply fighting over the female guppy. This can be reduced by adding floating plants, adding more females, or removing the females from the tank.
Fortunately, the fighting usually is not too harmful other than some nipped fins.