Take 'em down with one shot!
Falco Lombardi

Triangle Fighters are triangle shaped starfighters, manufactured in Macbeth's weapons labs, utilised during the Lylat Wars by Andross's Empire. 


Hence the name, Triangle Fighters are arrow shaped star fighters that normally fly in tight formations.

Formation frying

When you first reach the first Lock-on site shown, lock on the middle fighter in any formation to fry as many of the surrounding ships as possible with one shot. In some cases, you'll find items in the debris.
—Official Nintendo Power Player's Guide, pg 38

Double Whammy

As you approach the Grazan battleship, target its openings, because fighters will catapult out of both barrels. Lasers simultaneously spew out, too, so quickly veer to safety. After the assault, you can fly either above or below the ship's deck. Both paths deal you the same enemies: a squad of enemy fighters. The fliers appear at the the end of the Grazan, so keep your lasers charged.
—Official Nintendo Power Player's Guide, pg 62

Medal Tips

The fighters in this mission will usually attack in formation. Lock on and blast them. There are two places where the course forks. In both cases, take the upper path since you can get a few extra enemies that way.
—Star Fox

In the games

A Triangle Fighter (Gamma On) in Star Fox Zero.

Star Fox 64/3D

Triangle Fighters were prominent deep space, starfighters that made up the majority of the Venomian fleet massed against the Cornerian fleet at Sector Y. Peppy Hare instructed Fox to hold a garrison of Fighters flying out of a Grazan-class carrier in order to stop their advance on the Cornerian cruiser while trying to get through, while Falco Lombardi encouraged him to take out four squadrons of three each with one charged bolt. Slippy Toad was at one point chased by an overwhelming hoard of hidden fighters. More Triangle Fighters were sighted at the Meteo Asteroid Field and the Venom Air Defense Zone.

Star Fox Zero

Triangle Fighters reappear in Star Fox Zero under the names: Gamma On and Gamma Off.