Tetra Facts

Tetras don’t believe in going solo, even if they’re the only fish in your tank. Being alone can stress them out. They usually enjoy the company of at least five to seven other tetras of the same variety. But despite their fear of loneliness, they don’t form a tight pack unless threatened. They’ll shoal most of the time, but when one fish darts at them, they quickly bunch up together.

Some fish protect their eggs in bubble nests, while others carry their young in their mouths. Tetras are a bit old-fashioned and prefer to drop their eggs and swim away. Some types, such as bloodfin tetras, prefer to have certain plants around before they lay eggs. You’ll usually see eggs and fry appear if you have at least a 10- to 20-gallon sized tank. Both female and male tetras don’t have a great appreciation for their young, and they’ll eat the eggs and fry if given the chance. It’s usually better to remove the mature tetras for this reason.

The size of tetras depends on their variety. Neon tetras usually mature at a bit less than an inch in length, while flame tetras can get up to 2 inches. Most types range from just under an inch to 3 inches. The smaller tetras need a minimum tank size of 10 gallons, mostly because you’ll be adding six to eight instead of just one. Larger tetras that grow to over 2 inches should have a minimum of 15 gallons to swim in. The more tetras you add, the larger your tank should be.

If you have a specific color preference for your fish, you’re bound to find your color of choice in at least one type of tetra. Neon tetras have a silver body with neon blue stripes and a red color that stretches from the middle of their body to nearly the end. Flame tetras toss aside the blue stripes in favor of a red color that covers their back half, while silver covers the rest of their body along with two vertical lines on their front side. A lemon tetra has, as you might expect, shades of yellow throughout, with a touch of black on the anal and dorsal fins.

Tetra temperament is where aquarium owners get into trouble. Tetras can be excellent tank mates for numerous types of long-finned fish, such as angelfish and bettas. The more docile tetras, such as neon and flame tetras, coexist fine with certain types of fish. Tetras that nip at the fins of other fish, such as the Buenos Aires tetra and black skirt tetra, should never be kept with long-finned fish. And of course, you should make sure the other species of fish you're considering is also amenable to sharing a tank.