The serpae tetra (Hyphessobrycon eques) has previously been known as H. serpae and H. callistus, among other names. Callistus means “most beautiful” in Latin or “very handsome” in Greek. Other common names include callistus tetra, jewel tetra and even blood characin. The deep-bodied, laterally compressed serpae tetra is indeed beautiful, with a generally reddish-brown body and a dark band behind the gills. Serpae tetras have a tall black dorsal fin, while the long-based anal fin, the forked caudal fins and paired fins are generally deep red, making for an eye-catching fish that only grows to 2 inches.
Serpae tetras originally come from South America, where their preferred habitat is the slow-flowing streams and tributaries of the Rio Guaporé and Rio Paraguay basins in Brazil and Paraguay. In the dry season, they also occur in ponds and oxbow lakes (an oxbow lake is a crescent-shaped lake that was once actually part of the river). For the most part, the water is soft and slightly acidic (dH 5; pH 5.5 to 6.5). Sometimes, these localities do have some vegetation or fallen branches that offer some cover that the serpae tetras use. Today, though, the popular serpae tetra is bred by the thousands on fish farms to satisfy the demand for them by fishkeepers. In the wild, these tetras feed primarily on live foods, such as small crustaceans and worms, but also some plant material.
Serpae tetra do best in large shoals in big tanks. They can get a bit nippy so avoid keeping them with fish that have long and flowing fins.Photo by Faucon/Wikipedia
A 4-foot-long (48-by-18-by-24-inch), 90-gallon aquarium is ideal for a shoal of serpae tetras, as this allows enough space for the introduction of other species. The sides and back of the aquarium should be heavily planted, as this will allow some respite for the weakest members of the serpae group that want to disappear now and then. A 3-inch bed of smooth, small-grain dark gravel is deep enough to root plants of one’s choice. For instant results, select several pieces of Java fern (Microsorum pteropus) or Indian fern or water sprite (Ceratopteris thalictroides) rooted on bogwood, arranged so that there is a nice clear area for the fish to swim when they break from cover. Water in this aquarium, maintained at 75 to 82 degrees Fahrenheit, can be near neutral but not too hard (pH 7, dH 5 to 10). Water quality must be perfect (low in nitrogenous wastes). Regular partial water changes are also an important part of aquarium maintenance.
Do’s and Dont’s of Serpae Tetras
- Do keep them in shoals.
- Do provide ample swimming space.
- Do keep nitrogenous wastes low and water quality high.
- Do keep tankmates that are bigger than the serpae tetra.
- Do give them a varied diet that includes Daphnia, mosquito larvae and bloodworms.
- Don’t have slow-moving or long-finned tankmates.
- Don’t keep them in small groups of two or three.
- Don’t try to breed the serpae tetra in the main tank — a separate breeding aquarium is needed.
- Don’t keep them in a sparsely planted aquarium where weaker fish of the group have no place to hide.
- Don’t keep them in a small aquarium.
The choice of other fish for this tank is vast. Tankmates should not be slow-moving, nor have long, flowing fins; ideally, they should also be as big as or bigger than the serpae tetra. One could go for colorful rainbowfish from Australasia (red rainbowfish, Glossolepis incisus; Bosemani rainbowfish, Melanotaenia boesemani), or mid-sized danios or barbs from Southeast Asia (giant danio, Devario aequipinnatus; rosy barb, Puntius conchonius) or even similar-sized tetras from the Amazon (black widow tetras, Gymnocorymbus ternetzi; bleeding heart tetras, Hyphessobrycon erythrostigma). For the substrate level, choices include the South American bristlenose plecos (Ancistrus) and Corydoras catfish or various Asian loaches (orange fin loach, Yasuhikotakia modesta; emperor loach, Botia udomritthiruji).
In the aquarium, serpae tetras take all aquarium foods that they are offered, including flake foods. They should, however, be offered a varied diet that includes foods that form part of their natural diet in the wild, such as live Daphnia, mosquito larvae and bloodworms. Frozen equivalents make a good, readily accepted substitute that helps to keep them in prime health.
To breed serpae tetras, obtain healthy adult male and female fish, and a separate tank for spawning and rearing the fry. Soft and acidic water (dH 2 to 5, pH 5.5 to 6.5) at 80 to 84 degrees Fahrenheit is placed in the aquarium with some fine-leaved plants that will receive the tiny, translucent eggs. Keep the female in this aquarium for a week before the spawning attempt. Feed her live or frozen foods so that she fills up with roe.
When considering serpae tetras for the aquarium, remember that they are shoaling fish that do not do well if kept in ones or twos. In fact, this is when they can turn quite nasty and start nipping the fins of their tankmates. When they are kept in relatively large groups of eight or more, they become rather gregarious, keeping most of their attention within the shoal. There is a lot of chasing and some fin nipping within the group as they establish a hierarchy, but there is little damage done — split fins soon heal. Additionally, males will be continually strutting their stuff with a lot of fin-flaring displays that make for interesting viewing.
Introduce the male one evening, and the pair should spawn at first light. After the spawn, remove both adults. Eggs should hatch in 24 hours, and once the fry become free-swimming some four days later, feed them infusoria. Within a few days, they will be large enough to take brine shrimp nauplii and microworms, and then larger foods. Regular water changes and bigger tanks are needed to keep them growing well.
A shoal of serpae tetras adds color and flamboyance to any aquarium. They can sometimes be a bit boisterous with other species, but the best way to manage this is by maintaining them in a shoal rather than in twos or threes. Serpae tetras are hardy and easy-to-care-for. They will give their keepers a lot of pleasure with their antics.
Iggy Tavares has been keeping fish since the early 1960s. He studies and breeds popular freshwater fish; his passion is breeding, photographing and writing about cichlids.