Why Is My Swordtail Fish Aggressive?

Is your aquarium overcrowded?

Does your swordtail has an extended belly?

Does your aquarium have more males than females?

Are there little or no hiding spots in your aquarium?

In natural habitats fishes tend to remain harmonious and live peacefully since they have adequate space for themselves. In an aquarium tank, the space is limited and since the tank is overcrowded, stronger swordtails will draw their territorial boundaries. Therefore, any fish that crosses their boundaries is always chased and fought even to death. To avoid overcrowding, go for a larger tank or keep a recommendable number of fish in the available space.

Pregnant swordtails fish tend to be stressed. It is this stress factor that elevates their aggressiveness. Due to their critical condition, it is advisable to keep the pregnant swordtail fish in a separate tank until it gives birth to the livebearers. This will not only help to protect her from stress and interruption but also enable you to monitor her during the pregnancy hence giving you ample time to protect the livebearers from being eaten upon birth.

When the female swordtails reach sexual maturity, the male counterparts always follow them for mating. With more males in the tank, chances are that they will ever be fighting each other over females. Usually, the stronger male will dominate and develop aggressive behavior towards another male. So it is very important to keep a proper male to female ratio in the aquarium.

To provide a healthy habitat for your fish, you must provide enough hiding spots for them. Hiding spots work as a home and safe place for the fish whenever they detect some danger. If there are little or no hiding spots in your aquarium, the stress among them may increase and ultimately it will lead to aggression.

Male swordfish fights to maintain their territories. Just like any other animal, they feel the need to keep specific places in the aquarium to themselves. Hence, they will do whatever is necessary to maintain these specific areas. There are even cases when swordtail fish will kill each other. An alpha-male that has decided to express dominance to another sub-male will relentlessly chase the other sub-male any time even in the wrong direction.