The Dirt Cheap Discus (Article on Severum – ed. note)

It’s been years since I owned a discus. The discus I did own, back in my university days, were – well, lets face it – as boring as last week’s newspaper.

This actually came as a bit of a shock – with all the hype surrounding discus I thought they would be something special. But instead they were dull: mostly because they didn’t act anything like cichlids. Of course, my angelfish didn’t act anything like cichlids either, so I was prepared for that, but what shocked me was the discus didn’t act like angelfish either. At least my angelfish recognized me (the food guy) and acted excited when I walked in the room. But the discus just stayed where they were and looked down their noses at me with disinterested disdain. You’d think they’d get excited too given how much they ate. But it was as if doing anything besides standing still and gulping down the most expensive live food available was beneath them. If there ever was a snooty fish, the discus would be it.

Of course, I should have known they would be snobs. Just try to find an article or book about discus that doesn’t describe them as the “King of the Aquarium”. We mere commoners must not take the care of royalty lightly. They require the best of foods, the largest of tanks, the most efficient of filtration (that must never create a current strong enough to disturb them), and the very best water that reverse osmosis and black water extract can make. And, oh yes, one should never allow any of the lesser fish species to besoil a discus tank with its presence.


OK, so they really aren’t that bad, but no one can deny that discus are persnickety.

So why not avoid the expense of discus in favor of a fish that is just as regal, just as large, just as docile, but a lot more active? The severum.

OK. A severum isn’t quite a discus. There are a number of differences. The severum, while just as ‘laterally compressed” as a discus, has a profile that is more spade-shaped than the much rounder discus. Neither has the severum been bred into as many gaudy colour strains as the discus. But the severum is a good deal less neurotic than its discoidal counterpart. This means that the severum is less prone to various bizarre behaviors such as smashing into the walls of the aquarium at high speed for no apparent reason, or turning black and lying on their sides in a futile attempt to imitate a flounder.

And as far as feeding a severum goes, any experienced discus keeper will think that that the severum is a trash disposal unit in comparison to the picky discus. Everything from Cheerios to dandelion leaves, from flake food to beef heart, from cantaloupe to grapes, and from neon tetras to blood worms will readily disappear into a severum’s gullet. Try to get a discus to eat anything that sells for less than $1 a gram and watch them turn their noses up at it.

And severum’s are dirt cheap. Even young adults go for under $10 retail, a fraction of the cost of a discus.

Although the severum doesn’t have as many colour strains as the discus, there is one artificial strain that is sold…the “gold severum”. This is just a “melanistic mutation” (not quite an albino) that wouldn’t last two minutes in the wild. As an enthusiast of fish that look like nature intended I’ll forgo any further discussion on the gold severum and confine this discussion to the proper “green” (wild type) severum.

Admittedly, no wild-type severum can ever match the color of one of those ultra-neurotic, always-eat-their-own-kids, “fancy” discus strains. But a wild severum will get to be as colorful as any wild discus. And it is not any deficiency in color that makes the severum so much cheaper than the discus…its their ease of breeding and the laws of supply and demand. Not only are severums easy to spawn, they are very fecund, producing several hundred fry per spawn. A single pair of severums can easily swamp a local market for young severums with their offspring, thus driving the price down almost to embarrassingly low levels.

There are actually at least two different fish species sold as the severum. The Brazilian severum is generally thought to be Heros severus, while the Peruvian fish is Heros appendiculatus. The proper species designations for the genus Heros is however likely to turn out to be much more complicated than that. The commonly seen commercial severum most closely resembles the Peruvian H. appendiculatus, but is most likely some kind of mixture of fishes from various locales.

The commercial severum is an adaptable, resilient, and (when fully mature) magnificent fish. The basic background colour is an olive green, with a black vertical bar just in front of the tail. Their anal fins are flushed with ochre. The fish can also display dark green bars on a light background along the length of its body when the mood strikes it. I haven’t been able to correlate this display with any specific behaviour though, so I am not sure exactly what “mood” results in the dark green stripes. The adult males also display turquoise blue striations on the face and gill covers, making them very attractive. A mature dominant (wild-type) severum male is as striking as any real (wild-type) discus, but raising such a specimen is a slow process, and alas, only one male in a tank will ever reach its colourful best.

Severums are not aggressive fish and can be kept with other docile cichlids such as angelfish, festivums, uarus, members of the earth-eater group of cichlids (of the genus Geophagus, etc.), the South American dwarf cichlids, and yes, even with discus if the tank is large enough. Other suitable tankmates include any of the South American tetras and catfish that are not too large and not too small for any of the fish to consider the others a meal. Adult severums will swallow very small tetras, but any of the larger round-bodied tetras make fine tank mates. They should however not be kept with bullying cichlids like the Jack Dempsey or the Oscar.

Severums do best either when kept either as mated pairs or in groups of at least six. Because these fish grow to a length of over 20cm, a large tank is required. 100 liters is the absolute minimum capacity for a pair of severums, and a small group needs more than 200 liters. A community tank with a group of severums and any of the other large cichlids mentioned above would likely require at least 400 liters.

A planted tank is highly recommended, as severums (unlike discus) inhabit plant-filled streams in the wild. Water conditions are not critical for commercially bred severums and local Calgary water conditions are fine as they are. Softer, more acidic water may be necessary for wild-caught fish, however. Temperatures in the range of 24C to 26C are recommended, but my fish have experienced temperatures ranging from 18C to 32C without showing any distress whatsoever.

Severums will eat some plants, but are not voracious plant destroyers. I have had little problem keeping them in fully planted tanks. Of the common plant species, they seem to like to eat Amazon sword plants and temple plants more than the others. Java fern and val seem to be ignored totally. They will not uproot any plants except possibly just before spawning.

These fish are very hardy, and can be recommended as a first cichlid to anyone willing to supply a suitably sized tank. I have come up with several bizarre ways to try to kill my severums but failed each time. The severums are however my only fish to have come down with a case of ich in the last several years…but I cured this easily by simply raising the tank temperature to 32C for two weeks. The only thing I would caution the prospective keeper about is that it is very important to have a suitably mature biological filter in a severum tank. These fish seem to be very sensitive to ammonia, especially in our local alkaline water. As these are large fish, they can easily overload an immature filter if several are added to an aquarium at once, resulting in their deaths.

The diet of the severum should include some plant matter. My fish get a stable diet of a homemade gelatin food that contains zucchini, spinach, and carrots. A Spirulina flake food should also be included. They also feed upon invertebrates in the wild, so Daphnia and insect larvae should be included in their diet if possible. Like almost all cichlids, they are also astonishingly fond of earthworms, but these rich morsels should never make up the bulk of a severum’s diet or obesity and constipation will result.

Sexing severums is fairly easy provided you have one of each sex to compare. The largest individuals are almost always males, as females are usually some 20% smaller than males of the same age. The males’ anal and dorsal fins are also considerably more pointed than the females’, and a female in breeding condition has a much more pronounced belly than the male.

Spawning will take place in a community aquarium if the fish are dominant within that aquarium, but it will occur much more readily if the pair are given a tank to themselves. The fish will begin spawning by the time they are 7cm or so in length. They will usually spawn in typical substrate-cichlid fashion on a flat rock, but they may also choose the base of a vertical surface. The fry are guarded by the parents before and after they become free-swimming. All the severums in my experience made doting parents. Watching their parental behaviour is still one of the most fascinating aspects of the aquarium hobby. The fry can be reared on newly hatched brine shrimp and crushed Spirulina flake food. Growth is rapid at first, but slows considerably after the fish are 2cm or so in length. By that time you would have probably have had to get rid of most of the fry as it would be very difficult to raise all of them. When culling the fry do not however only choose the fastest growing fish as the keepers, because these will almost certainly all be males. Instead, rid yourself of all obviously malformed or stunted fry first, then if you still need to reduce numbers, choose the remaining fish to be culled more or less at random.

Severums mature quite slowly, and it may be almost two years before the young will breed. Expect at least another year after that before the males show their best colors. On the other hand severums are one of the longer lived aquarium fish and you can expect to keep your fish for well over ten years.

The severum is in my opinion one of the most underrated and under-appreciated fish in the aquarium world…a situation I can only attribute to the long period of time that a mature male requires to show his full colors. The juveniles that the stores sell are simply not flashy enough to draw much attention. However, for the aquarist with patience, the severum is one of the most rewarding fish available.