Last Updated: March 22, 2023 by Flora Gibbins
Guppies are nonviolent fish species, but some may portray aggression. Like any other species, a few aggressive outliers can tarnish the overall reputation. You can usually spot only one or two core aggressors in a tank full of guppies.
Does the buck stop at “are guppies aggressive fish?”
Not at all! It boils down to identifying aggression, forms of aggression, and how to fix the unfortunate situation. Let’s get right into it.
Aggression Patterns between Male and Female Guppies
Typically, male guppies are usually the chief antagonists in these aquatic wars. If you spot a more colorful, smaller fish with lean and longer fins smack in the middle of a confrontation, that’s your culprit right there. He most likely started the fight because they tend to be very domineering.
Meanwhile, the female guppies are the more prominent, drab-colored, and triangular-finned counterparts. They seldom project aggression and usually extend grace to fellow aquarium members.
Telling your fish apart is paramount when identifying the participants and cause of the aggression. How else will you recognize and protect the bullied guppies?
Male guppies are primarily driven into aggressive behaviors by their extreme mating tendencies, especially when there are too many males or only males in the fish tank. Overcrowding guppies in one will definitely brew hostility.
Also, keeping larger fish with smaller ones in one tank motivates the aggressor to dominate over the smaller and weaker party. The remedy here is to place only larger fish in one tank.
Signs of Aggression in Guppies
Constant Guppies Chasing
Guppies will sometimes follow other guppies around the aquarium in a non-threatening way and may even give the other fish a nudge or two.
As a sign of hostility, the aggressive guppies’ chase is usually constant with several violent contacts.
Frayed fins are a more apparent indicator of violent abuse. However, frayed fins can also be a matter of sharp aquarium decor. To protect your fish, remove all sharp objects from the tank, and replace them with smooth-edged ones.
Damaged fins and other bodily injuries may indicate an infection or disease.
Guppies swim constantly, and when they are fixed to a spot, hidden away from other guppies, something isn’t right. They also may be hiding from bright light or other fish.
You may also notice your fish never come within a couple of inches of the hostile guppy fish.
Dead Fish in the Tank
If guppies die of adverse bullying, their fins will be damaged and may have body harm. If not mitigated in time, the fish succumbs to the injuries. Damaged fish always escalate to infections and have no happy endings.
If you’re keen enough, as you should, you’ll always notice when something is off in the tank. It would be best to address the bullying before it gets to casualties.
Who Are Guppies’ Aggressive Behavior Towards?
Though generally peaceful fish, guppies’ aggression takes shape in different forms, stems from different causes, and has unique solutions.
Let’s scrutinize these aggressions and nip them in the bud.
As I had pointed out, male guppies’ aggressive behavior is the most common. It looks like their sympathetic nervous system chooses to fight whenever they feel threatened instead of flight.
Male guppies fighting each other could stem from issues like food scarcity in the tank, mating partners, or asserting dominance when they perceive territory encroachment.
Always keep more females, at least three female guppies for every male guppy in a mixed tank. Keep six or more in a male-only tank, but use a spacious aquarium, so they don’t feel threatened. When the males are multiple, the aggression is spread out and randomized.
Attacks targeting a guppy are usually devastating because the aftermath can never be positive.
Male-on-female aggression occurs mainly during their almost monthly mating season. Females are only drawn to the fairer fancy guppies with shiny coats for high-quality offspring.
Usually, dull-colored male guppies who fail to fit the bill use aggression in the form of fin nipping and chasing to intimidate the often younger females into mating with them. Male-on-female aggression can be to assert dominance.
Did you know that guppy fish have a social hierarchy? Their hierarchy is purely based on physical finesse. A dominant female guppy can be aggressive to other female guppy fish to show them who’s boss.
Usually, pregnant female guppies nip other guppies as they compete for more food, but this can be solved by installing a separate guppy breeding tank. When they experience food scarcity, especially during pregnancy, they become aggressive for sustenance.
Aggression towards their young ones is somewhat unexpected for such a friendly species. Sadly, female guppies do kill and feed on newborn guppy fry. This is why you’ll need a breeding tank.
Once the mother guppies are done reproducing, net scoop them out of the breeding tank and put them back into the community tank to increase the baby guppies’ survival chances.
This rare scenario is only likely when sickly male guppies get too close to their female counterparts. The female guppies force a social distance between themselves and the infected male fellows. The altercations become more common when female guppies are pregnant or during mating season.
It will help if you quarantine the sick fish to avoid spreading infections and diseases among fish. Only place them back in the community tank when you are confident they are fully recovered.
How to Combat Guppy Aggression
Are guppies aggressive? Now that we have a resounding answer, let’s assess and curb the menace in its roots. Guppies’ aggressive tendencies are boundless and could end with fatalities.
You can take several measures to stop or prevent bullying among guppies. Below are some of the simple adjustments you can make:
Rehoming the Aggressive Fish
You may have to relocate a proactive aggressor. Getting rid of the ‘bad apple’ may force you to dig into your pockets now that you’ll need another tank, but its effectiveness is unquestionable.
Please ensure that the new habitat is conducive. The conditions must be suitable for the guppies to thrive.
Improving the Male-To-Female Ratio
Lack of sufficient mating partners is a significant issue resulting in adverse male guppy aggression. Male guppies are also highly territorial and will fight to defend ‘their’ space.
The suitable male-to-female ratio is three female guppies to one male guppy. This way, the male guppies become less aggressive. The males also have more space and won’t have to swarm over a few female guppies. Males are always constantly competing for a female guppy.
Increasing the Gallons of Water per Guppy Fish
The issue may be too little space for too many guppies. Overpopulation is very difficult to battle as guppies procreate rapidly. After months of keeping guppies, the tank population can quickly get out of hand.
The most significant number of guppies per gallon should be one guppy for every 2 gallons of water. This ratio is the bare minimum, meaning most tanks are usually overpopulated. The scarcity that comes with crowding progresses into aggression.
Adding Hiding Spots
You can also consider putting artificial or live plants, toys, and smooth rocks in the aquarium. These can act as suitable hiding places, giving the victims a place to hide and heal. Plenty of hiding spots allow you more time to address aggressive guppy behavior.
Smaller guppies and fry can also escape from fin nippers by hiding in tiny spaces that only they can fit.
Serving More Food
Based on your knowledge or past experiences, I know that more food may not sound prudent. However, it is necessary when some fish are bullied off the food and have had little or nothing to eat. You should give them more food to avoid starvation and become violent fish.
Though bullying off food is typically an expression of dominance, bigger rations are the most logical response as they will leave behind some food for the underdogs once they’re full.
Fun Fact 1: Are you familiar with angelfish? Read our post, Are Angelfish Aggressive? 4 Reasons Why They Act Devilishly! to learn more about this attractive pet.
Fun Fact 2: In reference to Fun Fact 1, would you attempt to place an angelfish and a guppy inside a single aquarium tank? Read our article and find out if this is feasible — Angelfish And Guppies: Are They A Heavenly Pair Or Not?
Frequently Asked Questions
Are guppies aggressive to other fish species?
No. Guppies are generally pleasant and can share a tank with other fish. Though, oddities can get aggressive sequentially, giving guppies lousy press.
Guppies could get aggressive when their desired need isn’t being met. In ideal conditions, they are one of the most sociable fish in an aquarium.
Can aggressive guppies be tamed?
Naturally, aggressive guppies will attack their tank mates upon introduction. Removing such guppies and returning them to the store or keeping them in a separate tank would be wise. Such guppies may prove challenging to reform.
Removing the aggressive fish will stop guppies from conforming to hostile behavior.
Does bright lighting increase aggression?
Guppies are very resilient creatures and one of the most commonly kept aquatic species. One of the reasons is they can stay in light that other fish would consider too bright.
All the same, don’t abuse their endurance threshold. Bright light typically causes stress which leads to dull mannerisms, not aggression. It would help if you still controlled the lighting in the tank.
Indeed, aggression in guppies is an unfortunate occurrence. However, being more watchful will help your fish survive aggression better. Failure to keep a keen eye can be a financial and emotional setback for you and stressful to the guppies.
Luckily, there are numerous ways to contain an aggressive guppy. And it would be best if you promptly got on top of the situation to foster their well-being.