Serpae Tetra (Hyphessobrycon callistus)

The Serpae tetra (Hyphessobrycon callistus) is a tropical freshwater fish species which are sometimes referred to as jewel tetra, Red Minor Tetra, Blood Tetra, Callistus tetra, Blood characin.

This is an overwhelmingly beautiful fish that looks like a small moving flame in a tank. You won’t be able to take your eyes of serpae tetras school in an aquarium. This is a schooling fish and it feels better in a school. There should be at least 6 fishes in it and the fish can be kept together with some other fishes of the same size and activity level. The drawback of keeping tetras in a tank is their a bit troublesome temper – they can haunt and nip the fins of more slow fishes.

Inhabitance in the wild

Serpae (hyphessobrycon callistus, which was earlier called Hyphessobrycon minor and hyphessobrycon eques) was first described in 1882. You may encounter quite a lot of these fishes in the waters from Guyana to the river Paraguay in Brazil, in Guiana. The fish is rather spread one, it inhabits in impounded waters with lots of plants: tributaries, ponds, small lakes, prefer to stay close to water surface where they feed on insects, their larva and parts of plants.


Max size may be up to 4 cm (1,75 in) and its lifespan in the tank is about 4-5 years. The fish back is olive-brown and its sides are red, there is a small black spot on the fish opercle (sometimes it’s missing). The dorsal is black (sometimes it has white edges or only the ending). The rest of the fins are bloody red, all except the flesh fin.

Difficulties in keeping

Serpae tetra care isn’t difficult since the fish isn’t a demanding one. It lives in small volumed tanks and it’s not a fish that is hard to be kept in aquarium. Although the fish is easy in care it can become a problem itself when chasing and nipping the fins of slow fishes. Because of that you should be careful when choosing tetra tank mates.


Serpae tetra fish eats all types of live, frozen and artificial feed (for example Tropical Micro Pellet Fish Food or Hikari Tropical Semi-Floating Micro Pellets). Keep in mind that this tetra has a small mouth, so you have to choose small grained types of feed.

Keeping in a tank

A school of serpae tetras swims in the middle or bottom water layer in a tank. You can keep these fishes in a community tank (more than 60 cm (24 in) long) together with rather active tank mates. The tank should be thickly planted and there also should be some fluctuants which will shade the tank in some areas. Optimal water parameters for keeping are the following: water temperature within 22—24°С, water acidity 6—7, hardness 5—10°. The water should be transparent, clean and it’s advisable to use some turf to make it more alike the fish habitat.


Longfin serpae tetra is considered to be a proper fish to keep in community tanks, but it’s not exactly so. It’s true only if the fish neighbors with large and active fishes. The fishes that are smaller than serpae tetra will be haunted and pressured. The same is about any slow fishes with large fins, for example bettas or angelfish – their long fins will be constantly nipped, till the fish gets sick or dies.

Cardinal tetra, black neon tetras, Rummy nose tetra, Kuhli loach, bristlenose pleco are quite good tank mates.

However, if serpae is in a school, its temper becomes more calm regarding other fishes in a tank, since they have an hierarchy inside the school and the focus of the fish attention gets shifted onto their family. At that males pretend to fight with each other, however they don’t do any harm to each other.

Sex differences

It’s rather difficult to see between male and female. The difference between them is shown more before the spawning. Males are brighter colored and slimmer, their dorsal is completely black, on the contrary – the female fishes have pale colored dorsal and they are fatter regardless if they are going to spawn.


Becomes reproductive at the age of 8-10 month. You’ll need a separate spawning tank with the square of its bottom at least 700 cm², a protective grid and a bush of some small plants in the middle of a tank. The lights should be dim and soft. Water temperature should be within 24—28°С, general water hardness not more than 6°, carbonate hardness — not more than 1°, acidity 6—6,8. The water layer should be about 12—15 cm high. It’s recommended to use water with some turf in it.

The mixture can be prepared the following way: concentrated decoction of turf is added into defecated water, at the same time pH value is being controlled and then the water should be settled for a week (sometimes for a month). After that 2/3 of the water volume is poured into the spawning tank, however some fresh water can also be used. Take a female with rounded abdomen and 2 male fishes or a fish couple and put them into the tank in the evening, at the same time make the water temperature higher.

Quite often serpae tetra breeding starts before the sunrise and it finishes right when the sun is up. Feed the fishes with some blood worms 72 hours later. About 200-300 grayish eggs laid by the female fish get stuck on the tank plant leaves or fall on the tank bottom. The tank plants and protective grid are remover from the tank after the spawning. The tank should be shaded then to protect the eggs from direct light.

Some soft aeration is required. You shouldn’t touch the eggs, its very sensitive to this. Juveniles hatch in 24-30 hours after the spawning and they start swimming in several days (3-5 days). During this time interval you can switch on the aeration and the lights in the tank. Start feed for serpae juveniles is rotifers, infusorians.