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Related FAQs: Characid/Tetra Fishes

Related Articles: Characiform Fishes, 

To Subfamilies of Characids: Alestiine Characid Fishes, Characinine/Tetra Fishes,  Piranhas and Relatives, subfamily Serrasalminae, Tetragonopterine/Tetra Fishes, 

/The Conscientious Aquarist, /A Diversity of Aquatic Life

The Characid/Tetra Fishes, family Characidae,  In Aquariums

By Bob Fenner

Chalceus erythrurus

 18 genera, including Alestes (= Brycinus), Hydrocynus, Micralestes, Phenacogrammus and Rhabdalestes. About 109 species. 

(Excerpted from: Extreme Characins Part 2: Wolves, vampires, and other horrors by Neale Monks)    

Sidebar: Little jewels — small but fascinating oddball characins

There are lots of small oddball characins as well. Among the most interesting is the swordtail characin, Corynopoma riisei (4.8 cm/1.9"). This characin is unique in practising internal fertilisation; the eggs of all other characins are fertilised externally, with the male shedding milt over the eggs as they are deposited on the substrate or among plants. Female swordtail characins carry the fertilised eggs for more than 24 hours after mating, and so are able select the site where the eggs are deposited more carefully. Swordtail characin males live up to their name by having greatly extended fin rays on the lower half of the tail fin. Though not brightly coloured, these fish are lively and attractive, and make excellent community tank residents. They are schooling fish and very gently in temperament, and are best kept with other small characins, Corydoras, and peaceful dwarf cichlids. Swordtail characins have a reputation for being delicate immediately after import, but once settled in adapt readily to aquarium life and have proven to be long-lived and fairly hardy animals.

The darter characins of the genus Characidium are splendid little oddballs for the community aquarium. Several species are traded, but they’re all pretty similar and retailers rarely distinguish them. Characidium fasciatum and Characidium ranchovii are perhaps the two most widely sold, and at first either could be mistaken for a sucking loach or Siamese algae eater. Characidium fasciatum (10 cm/4") can be distinguished by a criss-cross pattern of short vertical bands set against a thick horizontal stripe running along the flanks. Characidium ranchovii (7.5 cm/3") on the other hand, is mostly unmarked except for a think dark band that runs along its midline. Unlike most characins, these are benthic fish that scoot about the bottom of the tank foraging for small invertebrates such as bloodworms. In aquaria, they are peaceful, non-territorial fish that adapt quickly to dry and frozen foods of suitable size. In terms of water chemistry, these fish prefer soft, slightly acidic water, and most critically the water should be clean and well oxygenated.

While a little larger than the other small oddballs mentioned here, Exodon paradoxus is at least regularly traded, lively, and very attractive. Known as the bucktooth tetra in the hobby, this characin is highly carnivorous and will eat small tankmates. Wild specimens are supposed to reach around 15 cm/6" in length, but aquarium specimens tend to be much smaller, typically 10 cm/4" or less. Maintenance with large community fish is complicated by the fact that these fish not only eat whole small fish but also the fins and scales of larger fish as well. So while some people have had luck combining them with robust fish such as plecs, the best way to keep them is in their own aquarium. These are intensely hierarchical schooling fish, and if kept in small groups the dominant individuals tends to bully the others, to the point where weaker are damaged or even killed. A dozen or more specimens may be an expensive investment, but only then will the aquarist get to watch their most famous behavioural trait: the feeding frenzy! Pretty much anything meaty is eaten, from flake and pellets through to frozen bloodworms and lancefish.