Are Gars Aggressive toward Other Fish?

Gars and gar-like fish are very predatory by nature. In fact, true gars grow too large for home aquariums, and are not recommended. However, several similar but smaller fish sell under the name "gar" in the aquarium trade. Their gar-like body shape means they are predators, and their tank mates need to be selected with care.

  1. Compatibility

    • True gars and smaller gar-like fish have a lot in common. Their body shape is purely adapted for hunting. However, this long, slender form is also somewhat delicate, meaning similar-size fish can easily damage gars. For this reason, many gars and similar fish get along well with some other fish, given two caveats. First, the fish has to be too large to eat, otherwise the gar will eat it. Additionally, tank mates need to have a peaceful demeanor, or they can easily injure or overpower the gar.

    True Gars

    • True gars, of the family Lepisoteidae, make awful aquarium fish. Several species are sold as juveniles by some pet shops, but these fish will rapidly grow to several feet in length. For example, the alligator gar is one of the largest freshwater fish in the world, and may reach several hundred pounds and up to 8 feet in length. They have sharp enough teeth to easily injure a person. This means they're best suited to public aquariums, not a home fish tank.

    Hujeta Gar

    • Hujeta gars are actually South American tetras. The tetra family includes a variety of fish, from the small, peaceful neon tetra to the infamous piranha. Hujeta gars have more in common with the piranha members of the family. These "gars" grow to 10 inches and will readily eat smaller fish. However, they themselves are vulnerable to fin-nipping. Also, hujeta gars do best in groups. These fish also sell under the name "pike-characins," another name for tetras.

    Needlefish

    • The needlefish (Xenentodon cancila) sometimes sells under the name "freshwater gar" or "freshwater barracuda." They need a large tank of at least 180 gallons, since they grow to about a foot long and are gregarious, schooling fish. Like the hujeta gar, needlefish are schoolers, and they are best kept in groups of four or more. They will readily eat smaller fish, but are very vulnerable to aggression from tank mates.