Head and Tail Light Tetra (Beacon Fish) Species Profile

Characteristics, Origin, and Helpful Information for Hobbyists

Hemigrammus ocellifer - Head and Tail Light Tetra
Chen Heng-Jou

Best known for its coppery spots that look like taillights, the head and tail light tetra hails from freshwater rivers and streams in South America. A peaceful schooling fish, this tetra species does not need a large tank. It does, however, need plenty of open swimming space and subdued mood lighting to keep it content.

Species Overview

Common Names: Beacon fish, beacon tetra, head and tail light tetra

Scientific Name: Hemigrammus ocellifer

Adult Size: 2 inches

Life Expectancy: 5 years


Family Characidae
Origin Argentina, Brazil, French Guiana, Guyana, Peru, and Suriname
Social Peaceful, schooling fish
Tank Level Mid-dweller
Minimum Tank Size 15 gallon
Diet Omnivore
Breeding Egglayer
Care Easy
pH 6 to 8
Hardiness 5 to 19 dGH
Temperature 72 to 79 F (22 to 26 C)

Origin and Distribution

Hemigrammus ocellifer originates in South America, where it can be found in numerous locations along the Amazon River and in the Orinoco river basin, as well as along the coast of Guyana. Favoring the slow-moving rivers and streams, it can be found in Argentina, Brazil, French Guiana, Guyana, Peru, and Suriname. Wild-caught specimens are rarely sold in the aquarium trade, as most are now captive-bred for commercial sale.

Their scientific name comes from the Greek Hemmigrammus meaning "half-line," which refers to an incomplete lateral line, and ocellifer, which means "eye bearing," a reference to the reflective spots or "eyes" on the head and tail of the fish. First described as Tetragonopterus ocellifer, this species was later moved to the Hemigrammus genus. 

Colors and Markings

Adults reach a length of approximately two inches (5 centimeters). The body of this fish is iridescent silver in color and, like many other tetras, is oval in shape. Seen from above, the body is compressed, and males are thinner than their female counterparts. The upper rim of the eye is edged in brilliant red, appearing similar to the redeye tetra. The body and fins are somewhat translucent, and on some specimens, a fine black line runs from mid-body to the spot on the tail fin.

Head and tail light tetras are named for two coppery colored reflective spots that resemble automotive lights. One is located at the base of the tail and the other is near the head next to the gill cover. These reflective patches are coupled with a black spot. The inheritance of this spotting pattern is of particular interest, since it probably serves as a deceptive "eyespot," mimicking the reflective red color of the retina of the fish's eye. 

Hemigrammus ocellifer falsus, has been named as a possible subspecies of this fish. It is more slender and has the “taillight” spot, but lacks the spot behind the gill cover.


Head and tail light tetras do best in schools of a half dozen or more and can be kept with other peaceful fish, particularly other members of the tetra family. Barbs, danios, rasboras, and other small to medium-sized peaceful fish are also good companions. Small loaches, catfish, dwarf cichlids, and the smaller gouramis are also suitable.

To avoid are fish that are large enough to eat tetras. Also note that head and tail light tetras may nip at the fins of slow-moving, long-finned species such as angelfish and bettas.

Head and Tail Light Tetra Habitat and Care

To see this little tetra shine, set up a biotope tank with real or artificial plants. Floating or tall plants that reach the top of the tank provide shade and are particularly desirable, as this fish prefers shady spots. 

Use river sand or a darker substrate, which will add to the subdued décor. Add a few driftwood branches and twisted roots. A few handfuls of dried leaves (beech or oak leaves are suitable) would complete the natural feel. Allow the wood and leaves to stain the water the color of weak tea. Remove the old leaves and replacing them every few weeks so they don’t rot and foul the water.

Add a small net bag filled with aquarium-safe peat to the filter to aid in the simulation of black water conditions. Leave some open swimming space in the middle to complete the ideal tank arrangement.

Head and Tail Light Tetra Diet and Feeding

Omnivorous in nature, the head and tail light tetra will eat most foods, but it will not nibble on live plants. Provide a good variety of flake foods along with freeze-dried or frozen live foods, such as brine shrimp, bloodworms, and small insects. They will eat fine pelleted food as well. Only live foods should be used when conditioning before breeding.

Gender Differences

Females are rounder and plumper than males, particularly when viewed from above. The internal swim bladder in the male is pointed and more visible than the rounded swim bladder in the female. Since this fish is translucent, it is possible to view the swim bladder by candling over a strong light.

Breeding the Head and Tail Light Tetra 

An egg-layer, this species of tetra is relatively easy to breed. The tank should be fitted with plenty of plants on which the breeder pair will lay their eggs. Lighting should be dim. Water in the aquarium should be soft, temperature 80 F (26 C), and with a slightly acidic pH in the range of 6.0 to 6.5.

Condition the breeder pair with live foods for a week or two. Bloodworms and brine shrimp are good choices, and frozen food may be used if live food is not available. As the spawning time approaches, the belly of the female will swell noticeably with eggs. Spawning typically occurs in the morning, with up to 1,000 eggs being laid over the course of the day.

Once the eggs are laid, remove the parents promptly; otherwise, they will consume the eggs and young fry. The eggs will hatch in 24 hours, and the fry become free-swimming within another two days. During this time, make sure the lighting continues to be very subdued. If the room is brightly lit, it is wise to drape the tank to reduce light. Feed the fry commercially prepared fry food, egg yolk, or Infusoria. Within a few days, freshly hatched brine shrimp can also be fed to the fry.

More Pet Fish Species and Further Research

If head and tail light tetras appeal to you, and you are interested in some compatible fish for your aquarium, check out:

Check out additional fish species profiles for more information on other freshwater fish.