Moderate
Blackwing hatchetfish (Carnegiella marthae)
24–28°C · pH 4–7 · 60L
£5.99
Schreitmüller's Silver Dollar (Metynnis hypsauchen) is a social, plant-forward Serrasalmidae fish for a long, mature aquarium. Keep at least six, plan 450L+ for adults, and provide 24-28°C water, strong filtration and open swimming room.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Product-photo provenance and any image-specific limitations are stated on the listing.
Metynnis hypsauchen
Schreitmüller's Silver Dollar are a shoaling species — they need 6+ to feel safe and show their full colour. Larger shoals stay calmer, eat better, and look stunning.
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Schreitmüller's Silver Dollar (Metynnis hypsauchen) is a social, plant-forward Serrasalmidae fish for a long, mature aquarium. Keep at least six, plan 450L+ for adults, and provide 24-28°C water, strong filtration and open swimming room.
Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size variant above for the actual shipping size. Product-photo provenance and any image-specific limitations are stated on the listing.
24–28°C · pH 4–7 · 60L
24–28°C · 30L
24–28°C · pH 6–7.2
23–28°C · pH 5.5–7.5 · 200L
Maintain these water conditions for optimal health and vibrant colors
Schreitmüller's Silver Dollar (Metynnis hypsauchen) is a deep-bodied South American shoaling fish for aquarists who can provide a genuinely large, mature aquarium. Its reflective silver flanks, quick coordinated turns and confident midwater movement give a group far more presence than a single specimen. This is the classic silver dollar fish rather than the separately listed Spotted Metynnis, Metynnis maculatus.
Young fish may be offered in several sizes, but the adult requirement is the deciding factor. FishBase records a maximum of 18 cm standard length, and the tail makes the practical total length greater. Plan for at least six fish, a long aquarium with substantial open swimming room, strong biological filtration and a plant-rich diet. This listing follows the supply identity Metynnis hypsauchen; the historical trade name Schreitmüller's Metynnis is explained below so the product remains clear to customers, search engines and aquarium-care systems.
Before you buy: this is not a small tetra and it is not suitable for a 200-litre community aquarium as an adult group. Use 450 litres and a 150 cm-long tank as a conservative planning floor, with 180 cm length and more volume strongly preferred for a settled adult shoal.
| Accepted listing identity | Metynnis hypsauchen (Müller & Troschel, 1844) |
|---|---|
| Trade names | Silver Dollar, Schreitmüller's Metynnis, Plain Metynnis |
| Family | Serrasalmidae |
| Natural range | Amazon and Paraguay river basins and rivers of the northern Guiana Shield |
| Adult size | Up to 18 cm standard length; allow around 20 cm total length when planning space |
| Social needs | Minimum six; eight or more preferred where aquarium size permits |
| Long-term aquarium | 450 litres and 150 cm length as a planning floor; 180 cm / 600 litres or more preferred |
| Temperature | 24-28°C |
| pH | 6.0-7.5, with stability more important than chasing a precise number |
| Hardness | Approximately 5-18 dGH |
| Diet | Plant-forward omnivore: vegetable matter first, with varied prepared and occasional invertebrate foods |
| Temperament | Peaceful but fast, powerful and easily startled |
| Swimming level | Middle and upper-middle water |
| Care level | Moderate, mainly because of adult space, group size, feeding and filtration requirements |
Metynnis hypsauchen is rewarding when its scale is understood before purchase. A group creates a bright, mobile centrepiece in a spacious South American or mixed tropical display, but juveniles quickly outgrow tanks designed for ordinary community tetras. The right keeper has room for the adult shoal, accepts that live plants may be eaten, and can maintain excellent water quality under a relatively heavy feeding load.
| A good match if you... | Choose another fish if you... |
|---|---|
| Have a mature aquarium at least 150 cm long, with a larger adult upgrade already available | Have only a 200-litre tank or cannot provide a long open swimming lane |
| Can keep at least six together from the start | Want one silver dollar as a solitary centrepiece |
| Are happy to use wood, stone and tough or replaceable planting | Need delicate stem plants to remain untouched |
| Can offer a vegetable-led diet and remove uneaten fresh food | Want a fish that thrives on generic high-protein flakes alone |
| Keep peaceful, similarly sized companions | Keep tiny fish, slow long-finned species or aggressive fin nippers |
This product is supplied as Metynnis hypsauchen under the common name Schreitmüller's Metynnis. Eschmeyer's Catalog of Fishes records the former name Metynnis schreitmuelleri as a synonym of M. hypsauchen, so the two names refer to the same accepted species identity in current cataloguing. The family is Serrasalmidae, not Characidae, although aquarium shops may still group silver dollars with tetras and other characiform fishes for navigation.
Silver dollar names are often applied loosely in the aquarium trade. Some stock historically sold as M. hypsauchen has later been identified as M. altidorsalis, and juveniles of several Metynnis species can be difficult to separate visually. For that reason, this page follows the recorded supply identity and avoids turning uncertain markings into a firm diagnostic claim. Customers specifically wanting a fish with obvious dark body spots should compare the separate Spotted Metynnis (Metynnis maculatus) listing.
Identification summary: this listing is Metynnis hypsauchen. "Spotted Silver Dollar" and Metynnis maculatus are not used as alternative names here because that is a different catalogue product.
The most useful silver dollar fish size figure is the adult one, not the centimetres shown on a sale variant. FishBase records 18 cm standard length, measured without the tail. A mature animal is also tall and laterally compressed, so body depth and turning room matter almost as much as length. A group can look comfortable as juveniles yet become crowded once every fish develops its adult disc-shaped profile.
For long-term care, plan from 450 litres and 150 cm aquarium length, treating that as a floor rather than an ideal maximum. A 180 x 60 x 60 cm aquarium, roughly 650 litres before displacement, gives adults much better scope for coordinated swimming and escape distance when startled. Width is important: a narrow tank may hold enough litres on paper but still restrict turning and group movement.
| Life stage | Planning priority | Practical guidance |
|---|---|---|
| Small juveniles | Stable mature water and a complete group | Do not split the group across temporary small tanks merely because sale size is small |
| Growing fish | Horizontal swimming length and filtration reserve | Monitor body depth, turning space, nitrate and feeding competition every month |
| Adults | 150-180 cm aquarium length, generous width and open midwater | 450 litres is a conservative floor; 600 litres or more is preferable for six to eight adults |
Silver dollars are social fish. Keep a minimum of six, with eight or more preferable when the aquarium has the capacity. A proper group spreads social pressure, reduces the insecurity seen in isolated individuals and produces the coordinated swimming for which the species is valued. One or two fish may hide, dash into hardscape or become unusually nervous.
Even a settled shoal can startle at sudden movement, lighting changes or maintenance. Position the aquarium away from constant foot traffic, provide shaded retreat areas and use a tight-fitting cover. Avoid sharp rock, exposed screws and narrow gaps: a frightened silver dollar moves quickly and can damage its deep body or fins. Introduce room lighting before the aquarium lights switch on, and avoid plunging the tank abruptly into darkness.
The recorded range for this line is 24-28°C and pH 6.0-7.5. FishBase gives the same temperature range and a narrower pH range of 6.0-7.0, while established aquarium references report successful maintenance up to pH 7.5. Choose a stable point within the overlap rather than repeatedly altering water chemistry. A hardness around 5-18 dGH is a practical captive range.
Filtration should be sized for adult biomass and a diet that includes fresh vegetables. Use dependable biological media, good mechanical capture and enough circulation to prevent dead zones without forcing fish to fight a relentless jet. Maintain zero ammonia and nitrite, keep nitrate controlled through testing and regular water changes, and ensure good gas exchange. A group breathing rapidly at the surface, clamping fins or losing appetite needs immediate water-quality and oxygen checks.
Stable-water rule: match temperature and chemistry to the fish you already keep, then change conditions gradually. A steady pH of 7.3 is safer than repeatedly pushing the aquarium toward 6.5 with short-lived chemical corrections.
Wild M. hypsauchen are described in scientific literature as herbivorous or omnivorous, feeding mostly on fruits, seeds, flowers and some small invertebrates. In an aquarium, build the menu around vegetable matter while retaining sensible variety. Calling the species a strict herbivore can be misleading; calling it an ordinary omnivore can lead to an excessively meaty diet. "Plant-forward omnivore" is the clearest practical description.
| Food type | Examples | How to use it |
|---|---|---|
| Daily plant-based staple | Quality green flakes, spirulina granules, herbivore pellets and algae wafers | Use as the nutritional base; distribute across the group so every fish feeds |
| Fresh vegetable matter | Blanched spinach, shelled peas, courgette, romaine lettuce and watercress | Offer clean, pesticide-free pieces and remove uneaten material before it decays |
| Occasional variety | Brine shrimp, mysis, mosquito larvae or another appropriate invertebrate food | Use sparingly rather than turning animal protein into the main diet |
| Avoid as a routine | Feeder fish, mammalian meat and large portions of fatty protein | These do not reflect the species' normal feeding ecology and add unnecessary waste |
Feed measured portions once or twice daily, adjusting for temperature, fish size and body condition. A hungry shoal can appear to need more than it does. Watch whether food is actually swallowed, remove leftovers and use nitrate trends to judge the total feeding load. Plant grazing is normal and is not always evidence that the prepared diet is deficient.
A delicate planted display and a large silver dollar shoal are usually competing goals. Tender stems, floating roots and fresh shoots may be eaten. Even Java fern and Anubias are not guaranteed to remain untouched. If living plants are important, test robust species in small quantities and accept that replacements may be needed.
A practical aquascape uses smooth wood, rounded stone and durable planting around the rear and sides, leaving an uninterrupted central swimming lane. Floating cover can soften the light, but keep enough surface open for gas exchange and feeding. Secure every heavy object before filling the aquarium; fast-moving fish should never be able to shift unstable rockwork.
Metynnis hypsauchen is generally peaceful, but "peaceful" does not mean suitable with every community fish. Adults are large, fast and powerful at feeding time. Choose robust, non-aggressive companions that share the same temperature and water chemistry and cannot fit into a silver dollar's mouth. Give each species enough room to occupy its own level without constant competition.
| Usually worth considering | Use caution or avoid |
|---|---|
| Peaceful medium-to-large characiform fishes in a very spacious aquarium | Nano fish, tiny juveniles and ornamental shrimp that may be treated as food |
| Robust Corydoras groups or suitable loricariids with compatible water needs | Aggressive cichlids, persistent fin nippers and territorial fish that control the whole tank |
| Calm South American species that do not depend on delicate planting | Slow long-finned fish likely to be stressed or outcompeted at meals |
| Other silver dollar species only where adult space and identification are understood | Mixing species merely to create a minimum shoal while keeping too few of each |
Use our aquarium care planner to review tank volume and care requirements, then research every proposed companion at adult size. The community fish collection is a starting point for comparison, not an automatic compatibility list.
| Catalogue fish | Identity used on our site | Buyer distinction |
|---|---|---|
| This product | Schreitmüller's Silver Dollar, Metynnis hypsauchen | The classic plain Silver Dollar identity; supplied under the historical Schreitmüller trade name |
| Spotted Metynnis | Metynnis maculatus | A separate species sold for its conspicuous dark body spotting |
| Silver Dollar | Metynnis argenteus | A very similar plain-bodied species that is often confused with M. hypsauchen |
| Striped Silver Dollar | Metynnis fasciatus | A distinct striped catalogue form; check current stock and adult requirements separately |
Common names alone are not enough when comparing silver dollar fish for sale. Check the scientific name, adult size, body pattern and selected variant before ordering. If replacing a fish in an existing shoal, compare clear photographs and provenance rather than assuming every "Silver Dollar" is the same species.
The size selector shows the available sale sizes for this product. Select the option that suits the established fish in your aquarium, but do not use a small sale size as a reason to postpone the adult tank. Very small fish need calm companions and careful feeding; larger fish need more transport and acclimation space. When adding to an existing shoal, a broadly comparable body size can reduce feeding imbalance and intimidation.
Stock and prices are live in the selector. Because availability changes, this description does not hard-code a price or promise that every size is in stock. For the wider range, browse tropical fish for sale in the UK.
Prepare the aquarium before dispatch: confirm temperature, ammonia, nitrite and nitrate; complete maintenance in advance; and ensure the cover is secure. On arrival, keep room and aquarium lighting subdued, inspect the sealed bags and follow the current instructions supplied with the order. Our acclimation timer can help you pace the process without guessing.
For the first week, watch the whole group rather than only the boldest feeder. Check breathing rate, fin position, schooling, skin condition and whether each fish receives food. Avoid unnecessary medication. If a fish is isolated, breathing hard or repeatedly colliding with the glass, test water and review group security, lighting and oxygen before assuming disease.
Sex differences become clearer in mature fish. Males tend to develop a more extended and colourful anal fin, while females are usually fuller through the body when conditioned. Juveniles are difficult to sex reliably, so a larger group gives a better chance of containing both sexes.
FishBase reports that M. hypsauchen spawns in schools near the surface and that the eggs hatch after about three days. Established aquarium references describe the adults as less likely to eat the eggs than many characiform fishes. Breeding still requires a separate, spacious setup with warm, soft, clean water, suitable spawning media and a plan for raising a very large number of fry. It should not be attempted in an overcrowded display aquarium.
FishBase records up to 18 cm standard length, which excludes the tail. Plan for roughly 20 cm total length and remember that the fish is also deep-bodied, so width and turning room are essential.
For a long-term group, use 450 litres and 150 cm length as a conservative floor. A 180 cm aquarium around 600 litres or more is much better for six to eight adults. A 200-litre aquarium is not an appropriate permanent home for the shoal.
Keep at least six. Eight or more generally produces a more secure group when the aquarium has enough adult space and filtration capacity.
Their water range is manageable, but their adult size, social needs, skittish behaviour and appetite make them a moderate-care choice. They suit a prepared keeper with a large mature aquarium, not a typical first small community tank.
Yes, plant grazing is normal and even robust species may be damaged. Build the aquascape around wood, stone and open swimming room, and treat live planting as experimental rather than permanent.
Use quality plant-based prepared foods and fresh greens as the foundation, with occasional suitable invertebrate foods for variety. Remove uneaten vegetables before they affect water quality.
Very small fish are a poor long-term choice because adults are large, fast and may treat bite-sized tank mates as food. Choose peaceful companions of an appropriate adult size.
No. This listing follows the supply identity Metynnis hypsauchen. The conspicuously spotted fish is listed separately as Spotted Metynnis, Metynnis maculatus.
Metynnis schreitmuelleri is a historical name now treated by Eschmeyer's Catalog of Fishes as a synonym of M. hypsauchen. The common trade name remains useful for identifying this supplied line.
Maintain 24-28°C with strong oxygenation and stable chemistry. Avoid rapid corrections to pH or hardness; consistency and clean water are more important than chasing a single ideal number.
Yes. They are fast, easily startled swimmers, so use a secure cover and remove sharp objects or narrow traps from the aquarium.
It is not responsible to plan for one. This is a social species and should be kept as a group of at least six in an aquarium sized for the adults.
Choose the required size from the live selector and confirm that your aquarium can support the full group at adult size. Every live fish order is covered by our Live Arrival Guarantee, subject to the claim steps and timing on that page. Current packing, delivery days, postcode limits and courier information are set out on our live fish delivery page.
New customers can use WELCOME10 for 10% off a first order where the code's checkout terms are met. The discount does not change the care requirement: order the number the species needs only when the mature aquarium, filtration and compatible tank mates are already in place.
