The Neon Tetra: A Simple, Friendly Fish

Neon tetra fish do not have aggressive personalities, so they do well in tanks with other types of fish. However, the other fish might not be as friendly, so pay attention to the behaviors of the other fish that you put in the tank. An aggressive species known to eat other fish could kill every neon tetra that you own — they’re only 1.5 inches long and don’t have many defense options, so they’re easy prey for most predators.

Some fish will attack and eat other members of their species. Neon tetras, however, seem to enjoy swimming in large schools. In the wild waters of the Amazon basin, swimming in schools makes their colors combine to confuse predators. When a predator sees a mass of colors, it will have a harder time picking out one fish from the rest.

The neon tetra doesn’t always rely on its bright colors for protection. In fact, when a single neon tetra gets scared that a predator is nearby, it can become transparent to blend into the background. The fish also become more transparent when they sleep, as they get older, and when they’re sick.

Neon tetra fish need an established tank of freshwater to live healthy lives. Do not put neon tetras in a newly cycled tank, as the chemicals in the water could kill them quickly. When you fill the tank, use soft water and keep the pH between 6.0 and 7.0. The fish do not need much filtration, so don’t invest in a filter that keeps the water perfectly clean — you’ll only stress your fish.

As you probably expect, fish from the Amazon basin prefer warm water. Keep your tetras' water temperature between 70 and 81 degrees Fahrenheit. During warm seasons, you might find that your fish enjoy room temperature, which, if it’s above 70 degrees F, shouldn’t let the water get too cold. During winter, though, you might need to add a heater to the tank. Check the temperature regularly to keep your neon tetras happy and healthy.

Neon tetras have a simple, cheap diet. Standard fish food — flakes or pellets — will keep them satisfied. If you want to give them something special, you can drop blood worm, daphnia (common water fleas), tubiflex (sludge worm), or brine shrimp into the tank. Live and frozen versions of these treats work equally well.

Neon tetras often live up to eight years in the wild. An aquarium will shorten their lifespan to about five years. You can help them live as long as possible by paying close attention to their water quality, feeding them high-quality, nutritious food, and keeping predator species out of the tank.

If you enjoy breeding fish, then neon tetras probably aren’t the best species for you. In the wild, they reproduce during a specific mating season. You can only get them to breed at home by perfectly reproducing the water conditions of their mating season in the Amazon basin, which is tricky. If you do want to try, you need a breed tank to separate the female and male fish. Adjust the pH level to somewhere between 5.0 and 6.0 and get the temperate a little under 75 degrees.

Neon tetra disease is caused by a parasite that attaches to the fish’s intestinal tract. There isn’t a cure, but knowing the symptoms can help you spot the problem and remove sick fish before others get ill. Common symptoms include sudden loss of color and a shrinking stomach or cysts on the stomach. The fish may also stay at the bottom of the tank. The parasite can hurt other types of fish, too, so get ill neon tetras out of your tank as fast as possible.

Since neon tetras like spending time around each other, buy as many of them as you want. Just make sure that you have a tank that’s large enough to support your school. Ideally, purchase a 10-gallon tank for a small number of neon tetras. If you want 15 to 20 of them, use at least a 20-gallon aquarium.