Green Severum Care Guide - Aquarium Setup, Diet & Breeding

The Green Severum is a deep-bodied, laterally compressed cichlid with a predominantly greenish to olive-brown base colour. Subtle vertical bars, iridescent blue-green markings and warm reddish or orange tones around the fins and face can become more noticeable when the fish is mature or displaying. Its rounded profile and long dorsal and anal fins give it an elegant appearance despite its substantial adult size.

This species is intelligent, observant and often develops a recognisable personality. Green Severums commonly investigate activity outside the aquarium and may learn to associate their keeper with feeding time. They are generally less relentlessly aggressive than many large Central American cichlids, although they can become territorial, particularly when paired for breeding.

In nature, Green Severums are associated with calm waters containing submerged roots, branches, leaf litter and dense marginal vegetation. Their body shape and behaviour suit manoeuvring through flooded woodland and plant-filled shallows rather than fast-flowing open water. They often browse surfaces and sift through the environment while searching for food.

Heros efasciatus is one of the severum species commonly kept in aquariums, and the name Green Severum is also used broadly in the hobby for the natural green form and closely related commercial stock. Individual colouration varies with age, mood, diet and social conditions, with mature fish often showing stronger patterning than juveniles.

Green Severums are native to northern and central South America, particularly the Amazon and Orinoco drainage systems. They inhabit slow-flowing rivers, tributaries, flooded forest areas and other warm freshwater habitats in countries including Brazil, Colombia, Peru, Venezuela and the Guianas.

A single Green Severum should have at least 250 litres, with a larger aquarium of around 300 litres or more preferable for a mature pair or community. A footprint of approximately 120 × 45 cm is a sensible minimum for one adult, while additional length and width are valuable because these fish are deep-bodied and territorial. Use fine sand or smooth gravel, sturdy driftwood, rounded rocks and robust plants attached to wood or rock; delicate rooted plants may be uprooted or eaten. Leave open swimming space, provide visual boundaries and use secure equipment and a tightly fitting lid.

Up to approximately 20 cm (8 in) in adult length. Males are often larger and more heavily built, while females commonly reach around 15–18 cm (6–7 in), although size varies with genetics, diet and aquarium conditions.

Green Severums are omnivores that benefit from a varied diet. Use a quality cichlid pellet or granule as the staple, supplemented with foods such as earthworms, insect larvae, brine shrimp, bloodworms and mysis shrimp. Spirulina-based foods, blanched spinach, peas and other suitable vegetable matter help reflect their tendency to graze on plant material and organic growth. Avoid relying heavily on fatty mammalian foods, which can contribute to digestive problems and poor health.

Green Severums can live with other peaceful to moderately assertive South American fish of a similar size, including larger tetras, peaceful medium-sized Geophagus, angelfish, larger Corydoras and suitably sized peaceful plecos. Tankmates should have enough space to avoid territorial disputes and should not be small enough to be swallowed. Avoid fin-nipping species, highly aggressive cichlids and delicate fish, as well as very small tetras and shrimp. Keeping multiple severums may work in a spacious aquarium, but adults can become territorial and a compatible pair may exclude others.

Green Severums are substrate-spawning cichlids that usually form a bonded pair before breeding. Offer a smooth rock, slate tile or other suitable spawning surface, and condition the pair with a varied, nutritious diet. The female lays adhesive eggs on the chosen surface, after which both parents typically fan and guard them. The eggs usually hatch within a few days, with the fry becoming free-swimming several days later; newly free-swimming young can be raised on appropriately sized foods such as freshly hatched brine shrimp.

Mature males are usually larger, deeper-bodied and more strongly patterned than females. Males may also develop longer extensions on the dorsal and anal fins, while females are often slightly smaller with shorter fin streamers; these differences are variable and not always reliable in young fish.