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This page will give a completely detailed profile of the selected fish, from A to Z. The profiled fish will be chosen randomly by Badman, and will come from the complete genre of tropical fish. New profiles are added on a regular basis. If you would like to submit a profile for the site please contact me. Don't forget to let us know you experiences with this fish by filling out the

South America


Metynnis hypsauchen
Metynnis hypsauchen

Metynnis hypsauchen
Metynnis maculatus

Metynnis argenteus, Metynnis hypsauchen, Metynnis maculatus


    One of my favorite fish. The Silver Dollar is a peaceful schooling species with a great personality. One word of caution they love greens and will completely defoliate a fish tank in no time at all. They should have some short of vegetable supplement in their diet. There can be some species confusion in the pet stores and when young they can be difficult to iodentify. They have the same basic needs.

Quick stats:

    Listed tank sizes are the minimum
    Size: Up to 8" (20cm)
    Tank: 48 inches
    Strata: Middle
    PH: 6.0 to 7.5
    Hardness: Soft to medium. dH range: 4.0 - 18.0
    Temperature: 75°F to 84°F (24-29°C)


    Order: Cypriniformes
    Suborder: Characoidei
    Super-Family: Characidoidea
    Family: Serrasalmidae
    Genera: Metynnis

Common name

    Silver dollar, Schreitmullers' Metynnis

Image gallery:
    Additional species photographs


    Badmans' Forum


    Widely distributed throughout South America, from Guyana to Paraguay, including the Amazon river basin.

General Body Form
    Basically circular in shape, as long as tall, with very marked lateral compression. The front on profile of the back and stomach are not uniformly convex (out ) , but rather curve in at the Dorsal and Anal fin level. Like most members of the family (Piranha included!) they have tiny scales with small mouths and enlarged lips. The Caudal fin is slightly indented, the Adipose fin is long and short and in mature males the front part of the anal fin is crescent shaped. They can reach a size of five and one half inches, with the males smaller than the females.

    The entire body is basically a strong Silver/Gray, with a high iridescence, which is highlighted when the fish are in a large school. The back is slightly darker being Greenish/Gray or Greenish/Blue in color. The Anal fin has a pale tinge of Silver color in the front that fades toward the back. The Dorsal fin is clear with a series of small dark spots. In well cared for males, the Caudal fin and the Gill cover have a Reddish border. A narrow, dark vertical band runs through each eye. As with most fish there are color variations.

    Shallow areas of their home range that are heavily vegetated

    The Silver Dollars require a large tank, a standard 55 or 40 gallon would be fine. The tank should have no live plants as this species is mainly vegetarian in habit. The substrate should be dark in color with subdued lighting. They are schooling fish and will always be shy and skittish in a small tank, so give them as much room as possible. The diet should primarily include plant material, particularly Romaine Lettuce, along with the various live foods. Water quality is not critical and the temperature should be kept in the upper Seventies to low Eighties.

    In nature these fish spawn in shallow, sun drenched flooded areas of rivers. In the home aquarium they have been breed in clear aged water with a temperature between 81 and 90f. The eggs hatch in about four days and are free swimming a week later. If well fed they will grow very quickly.

silver dollar
silver Dollar

Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Maude
I bought 4 silver dollars a month ago and they have been a great addition to my tank. It is a heavily planted 55 gallon community tank with loaches, catfish, the odd tetra and kribensis. The silver dollars are big eaters and are growing well. They have had a nibble on the bolbitis, a token bite of the Java fern, but the anubias plants are fine. I planted some crypts yesterday as an experiment and they were nibbled overnight - novelty value I think. I have not experienced any decimation of my plants, as others have - phew! The silver dollars eat a wide range of foods, black worms, bloodworms, shrimp, flake, algae and carnivore wafers, cos lettuce, zucchini and peas. They are very fast so I have to make sure the bottom dwellers get enough to eat. The silver dollars will swim around with a chunk of wafer in their mouths with the yo-yo loaches trying to feed on it. Quite funny to watch! Overall they are a peaceful and pretty fish, not at all shy or skittish. The heavy planting, dark background and natural gravel help make them feel quite secure. Give them a go - just allow for their full size and make sure you have a decent filter.
It's been nearly 2 years and the silver dollars are doing well. I went on holidays and the bolbitis and some of the anubias got eaten. I think the silver dollars remembered they were vegetarian when their food supply became irregular. The Java fern has not been touched and grows so well that I cannot give it away. There is a large water sprite floating around which they don't seem to touch either. I'm half contemplating throwing in some duckweed for the fun of it.
From: Laurie
I have four Silver Dollars which are about a year old. They are in a 55 gallon tank with four tiger barbs, one bristlenose, one cory and nine neon tetras, and one rainbow shark. The Silver Dollars have orange markings on their fins and have a lot of black spots, some more than others. They all chase each other and shimmy one another. They are sometimes timid, but they have grown accustomed to my voice and know that I am the food bearer, so they often meet me in the front of their tank, probably hoping for food. They are very social - they respond to my voice. They look at me through the glass and seem to dance around doing circles, a little like they do with each other when they are interacting amongst themselves. I really love this fish. They need a LOT of room though, no tank smaller than a 55 gallon. My fish are already about 4 1/2 inches in diam and in length. They are big eaters. They get a variety, frozen brine shrimp, bloodworms, flakes, vegetable crisps, lettuce or spinach. Sometimes I'll give them live brine shrimp as a special treat. They would eat all day if I fed them, but I have cut down from twice a day to once a day. They are happier in a school, but because of their size, this can be a drawback. I don't recommend keeping less than 3 if you want happy silver dollars! Happy Fishing!

From: new2aquariums
I have 5 3-4inch silver dollar fish in a 40g tank with natural day light and I have found them to be extremely tolerant fish of water conditions. They ate all my plants within a day and regularly feed them Spinach, lettuce and cucumber, they are extremely picky eaters when it comes to pellets and flake food. I have also recently experienced them not eating their food and praying on my tetra’s (this is rare but can happen as they are a the same species as piranha except they are vegetarian). They will also eat any baby fish you may have (witch can be good for population control). Extremely playful but shy with good memory, if someone scares them they will hide the next time that person is near the tank but will play happily when they leave.

From: Murgen
9 silver dollars in a planted tank. Bad idea. Should have researched them better before buying. My fault. Sold them to a friend after they ate every plant down to the substrate. Kind of a skittish fish Imo. They always seemed nervous in my tank, maybe too much light for the plants bothered them. They grew too big for my 55g as well. For a large open water tank with subdued Lighting they probably would be happier.

From: Pamelal Wildt
I have 7 SDs in a 75 gallon tank. They are a very peaceful fish and they play with each other all the time. Mine range from 4" to 7" and are still growing. Several are pink and also a couple have a lot of black designs. Only one is silver. They are constantly rubbing up against each other and shaking. I've only had them a half year and they are a delight. Fussy eaters. I feed them algae tablets, greens, flakes.

From: Greg Targett
I have 100 gallon tank with 4 common sliver dollars and 2 red hooks these are one of the most peaceful fish and some of the most interesting fish I have ever owned. I brought my first two SD a couple of years a go and fell in love with there behavior so I had to get some more. My fist 2 SD are about the size of a tea plate and still growing. My two red hooks are growing fast and love lots of open space and chase each other around and around the tank but are not aggressive to each other these are about 6 inches in length a great addition to any tank they are a bit expensive but well worth the monies as they get bigger so does the red hook. My other two silver dollars are about 4 inches in length and have joined the other fish as one big happy family. In the last couple of days 2 of the silver dollars are getting very friendly following side by side shaking there bodies at each other also the red fins have turned black and 2 black spots have appeared on there sides this behavior is amazing to watch. But I will have to look out for eggs very closely over the next few days. Every one should have some silver dollars in there tank. I will keep you informed when the eggs.

From: Maria
I have five silver dollars in a 60 gallon tank, I bought them at around 2 inches and they've grown around one or two inches since I got them. They were skittish at first (especially while acclimating them -- a lot of them would even play dead!) but as they got used to their surroundings, found their hiding places (they like a big sunken ship decor, and often they all hide in there) and realized that I was the food person. Now whenever they see me they will come near me, and will follow my fingers if I open the lid until they get something to munch on. They're not picky eaters -- I've feed them fish flakes, zucchini, frozen brine shrimp and frozen blood worms with no problems. They do love their plants though...!!! Immediately the first day I put them in the tank they started nibbling down my plants, and now every plant I put in the tank is condemned to look like a dead stick in a couple of days. Still looking for that wonderful plant that will not be eaten by these fish! They get along fine with all of the fish that they're with -- Angelfish, Powder Blue Jack Dempsey, Pictus Catfish, Raphael Catfish, and a Pleco. Other fish won't mess with them (even if they're more aggressive species), but that's probably because they're twice the size as most fish, and there's a lot of them!

From: Harvey
I should add that this fish may play dead when you acclimate them it's new home. Don't be alarmed they will be swimming freely within a day or so and once used to a normal feeding habit will be lively. I've bought these before and there's many types out there. I personally like Red Hooks but I have common ones cause Red Hooks are expensive.

From: Gareth lewis
I find that the best plants to keep with silver dollars are crypts all varieties. As regarding breeding. You know when they are they are ready to breed. The male fins will shine with a red tinge and the female develops two black spots behind the gill covers. They will chase each other round the tank then start egg scattering on plants or stones.

From: Maria Jones
Hiya I have three silver dollars I find that they don't touch Java fern Java moss or moss balls so if you want to have real plants in the tank these are the best!

From: Andrew Mowbray
I've read alot of comments about it being foolish to put live plants in with silver dollars but I place live plants in my 90 gal tank specifically for my silver dollars. I have two very large SD's and they do like my plants but they never ruin them or completely devour them, in fact I feel it is worth the small investment to give them a large variety of thing to nibble on. I also have a few large angel fish in with them who are extremely aggressive, however the SD's always seem to hold their own and are never intimidated. I do appreciate learning new things about my fish but I also must say I find all fish to have individual needs even within their own.

From: Brian
I enjoy my Silver Dollar. Not knowing much about the fish at the time I bought him, I have probably broken most of the conventional rules regarding keeping them but he appears no worse for the wear. I have a 20 gallon tank. When I bought him he was about the size of a quarter, he is now roughly four inches long not counting his fins. He seems quite happy by himself. He will go through periods of swimming back and forth and up and down; and then he will take a break swimming slowly or hovering; and then repeat the process. My two albino cories often join him and its quite a sight. He is more active than not though and brings quite a bit of life to the tank. He stays in the mid-strata most of the time except when feeding. He will eat at the top (his main diet is flakes although I feed him other treats too) and in the middle. He also has a habit, once the primary feeding is done, of looking very selectively in the gravel for scraps for a minute or so. I also feed him about every other day a very light boiled piece of spinach. He seems to relish this. He also likes tubifex worms and shrimp pellets. Sudden movements will scare him but otherwise he is not that skittish. He is generally the largest fish in my little tank and yet is generally peaceful. The only exception is with fish with wavy fins. I don't know if this is related to them being vegetarians and perhaps finding some wavy fins to be leaf like, but I have noticed he would try to nip the fins of an angelfish I once had (but only when the angel got very close). I would agree that they eat voraciously and he splashes quite a bit when he eats, making feeding time quite a spectacle. A fun fish to keep.

From: Pamela Kennedy
I've read alot of comments about it being foolish to put live plants in with silver dollars but I place live plants in my 90 gal tank specifically for my silver dollars. I have two very large sd's and they do like my plants but they never ruin them or completely devour them, in fact I feel it is worth the small investment to give them a large variety of thing to nibble on. I also have a few large angel fish in with them who are extremely aggressive, however the sd's always seem to hold their own and are never intimidated. I do appreciate learning new things about my fish but I also must say I find all fish to have individual needs even within their own kind. They're kind of like my children and all children are different.

From: Nedinska
I have 2 Silver Dollars which I have had for the last 4 years. Both are larger than the bottom of pop cans and I agree largely with the other comments about feeding and their love of live plants. I have found too, though, that my fish are particularly skittish and prefer to live in a dark tank. I sometimes turn the hood light on but find that the two just huddle in a corner. The minute I turn the light off, they are back out swimming. My fish seem to prefer the natural lighting that gets into the tank during the day rather than the artificial lighting of the hood.

From: PJ Cham
After new tank had been established and cycled for 3 months I purchased 3 Silver Dollars (LFS only had 3 in shop). Great addition to tank. I made a note of the dates of purchases and sizes of fish. The New Silver Dollars were all 35mm long (not incl tail). Exactly 2 months later they are 85mm long (Be aware, still growing). They are in a 4ft tank with group of Cories and doing very well although I intend to move them to a larger tank in future. They take most food incl catfish pellets and flake but Love frozen bloodworm and algae wafers. As soon as wafers are dropped into tank each Silver Dollar collects one pc and keeps in mouth, slowly nibbling away until gone. By adding several wafers at a time this means the cories are undisturbed to have their turn. Shy fish so ensure they have some places to hide even when then get larger. Can be jumpy so better if there are no sharp rock edges or decor in tank.

From: Kristin
I haven't found much on the web about silver dollar breeding, my pair have just had babies so here's some info: The time of year here in New Zealand is early spring (Sept) which apparently is a good time for fish to start their breeding. My male started getting a very dark edge to his tail and also top fin, 2 dark spots appeared on his side about the size of a thumbnail and he got an orangy red patch around the bottom of his gills. He would chase the female around alot and frequently would join his bottom half with hers and wrap is bottom fin under her and jiggle for a couple of seconds. I changed them to my other tank by themselves when I saw this. Just under a week later I noticed small fry swimming around, I can only count about 15. I've read that the eggs fall from her in between the gravel and hatch there but I didn't see this. Although I did notice dark long things on the wall of the tank that looks like small patches of algae about the same size of the babies so she might have stuck them there? They all swim separately not in a group and feed off the algae in the tank, I bought some fry food but they don't really feed from the surface so Im hoping that it will be a OK diet until they get bigger. Their size is about 5mm long and 2mm high. Apparently also they make good parents and don't eat their young but I put a large leaf of lettuce in there every second day, weighting it down with a peg just in case they get too hungry. I've kept the water temp at 26C and the pH level is around 6.6 to 6.2. When cleaning the tank I would recommend no vigorous movement and do only slight changes in water every week. I hope this helps anyone wanting to breed their silver dollars. I've had mine for over a year and they've only just started doing this.







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