The Fathead
A Minnow that thinks like a cichlid!


Dr Peter Burgess of the Aquarian® Advisory Service,
PO Box 5059, Melton Mowbray, Leicestershire LE14 4ZN

Is it a cichlid? Is it a small Golden Orfe? No, it's a Fathead Minnow!
The amazing diversity of fishes ensures that there are exceptions to every rule and the Fathead is indeed an exceptional minnow. It is one of a small number of minnow species (family Cyprinidae) that guard and defend their eggs, in contrast to the vast majority of cyprinids which abandon their eggs immediately after spawning.

The Fathead ensures that its progeny are given a helping start to life, thereby improving their chances of survival, a characteristic which is usually associated with the cichlids and anabantids.

"Fathead" seems a rather uncomplimentary name for this unusual fish but it accurately describes the thick, semi-translucent pad which extends from the nape to the dorsal fin of mature males. Seen from above, this pad resembles an elongate blister, and when viewed head-on, the fish assumes a very odd appearance!

Geographical distribution

In the wild, the fathead occurs throughout much of North America, being recorded as far south as Louisiana and across the Mexican border into Chihuahua, its northerly range extending up into the cold wilderness of Canada's Great Slave Lake region of the North West Territories. Fatheads occupy a range of habitats, including lakes, ditches, brooks and even beaver ponds, but generally they do not inhabit fast flowing streams or rivers.

Enter the morph

The wild-type Fathead Minnow was never a serious contender as an ornamental coldwater fish, for it has a rather drab coloration, ranging from olive green to brown above and silvery white below -hardly a match against the Goldfish, Bitterling or Golden Orfe. Fortunately, however, an attractive yellow-orange colour form has recently emerged in captive bred stocks. This yellow or "xanthic" morph (it has pigmented eyes and is not an albino) has occasionally been sold in the UK, under the names “Golden Minnow” or “Rosy Minnow”.

Unfortunately, most of the Fatheads offered for sale in this country have tended to be juvenile specimens, often in an emaciated condition. Very occasionally, the original dark colour form finds its way into the aquarium shops. Some xanthic specimens show dark patches on the body, probably representing a genetic throwback to the wild type.

Aquarium care

Reaching only 3 inches in length the Fathead Minnow is ideally suited to relatively small aquaria where it will peacefully co-exist with similar sized fishes.
Fatheads can be kept together in groups, or in mixed-species communities, or simply as a pair maintained alone in a 3-5 gallon aquarium. The fish are quite hardy in terms of aquarium requirements, tolerating tropical conditions to around 28oC although unheated aquaria held at room temperatures, between 16-24oC, suit them well.

Rockwork is an important feature of the Fathead aquarium and in this respect the fish should be housed as if it were a cichlid rather than a cyprinid. The decor should include half flowerpots positioned to form arches, plastic pipes (1.5 to 2.5 inch internal diameter) and slate caves, these structures being preferred as spawning sites.

Aquatic plants are not necessary but can be included to provide extra cover: unlike cichlids, Fatheads do not dig in the gravel and do not uproot plants. Fatheads tolerate a wide range of water conditions such that I have bred and raised them in soft, acid (pH 6.4) and hard, alkaline (pH 7.5) waters. The fish seem to prefer soft lighting.
No special requirements are necessary with regards filtration - I use a small internal power filter plus mild aeration.

Food requirements

The long intestine of the Fathead, being over twice its body length, is a typical feature of cyprinids and suggests a dietary requirement for significant quantities of vegetable matter. This is borne out by studies on wild specimens in which the stomachs were generally found to contain large amounts of algae together with zooplankton, insect larvae and organic material.

Under aquarium conditions Fatheads readily take flake or small pellet foods but given its natural food preferences, a regular supplement of vegetable flake (e.g. Aquarian® Herbivore flake) would be appropriate. My specimens also enjoy live or frozen Artemia, Bloodworm and Daphnia.
Fatheads are enthusiastic feeders but are not aggressive at meal times, taking food directly from the surface or mid-water as well as foraging head-down over the substrate.

Sexing and breeding

In mature fish the sexual differences are obvious. Males are the larger, their bulk being exaggerated by the thick dorsal pad which extends from the nape to the beginning of the dorsal fin. The female possesses the typical "minnow" shape, similar to our native Minnow (Phoxinus phoxinus).
In sexually mature males the first dorsal ray is separate and is thick and blunt and the fish develops smallish white "nuptial" tubercles which are distributed mostly over the snout. The ripe female will be swollen slightly with eggs, however in contrast to the wild form, the yellow morph female never bulges dramatically, at least not in my specimens. She also develops a short, thick tube near her vent, known as the ovipositor, through which the eggs are passed; this is another feature shared with the cichlids. The male possesses a smaller, thinner tube during breeding time through which the sperm are released.

The following conditions have proven successful for the aquarium spawning of Fathead Minnows, however they should not be regarded as hard and fast rules as these fish readily breed in captivity. Dietary conditioning is important and I generally increase the proportion of live/frozen foods whilst maintaining green matter. As with many temperate freshwater fishes, an increasing water temperature is one of the key triggers to breeding activity.

Spawning occurs when water temperatures rise above 17-18oC, although spawnings at lower temperatures (down to 15.5oC) have been cited in the scientific literature.
As far as age of fish is concerned, I wait until they are one year old before allowing them to breed, however there are recorded cases of Fatheads spawning at three months. The fish will breed in community aquaria.

At room temperatures, around 22-24oC, Fatheads may spawn as often as every 5 days, but this frequency may ultimately affect the health of the females.
For this reason, it is wise to occasionally separate the sexes, for 4-6 week periods, in order to rest the females. Pre-spawning behaviour usually occurs close to the site where the eggs will be laid, such as within a flowerpot. The pair go through pre-spawning embraces, swimming side-by-side and twisting upside down. Eventually the female deposits a few eggs which are simultaneously fertilized by the male.
The eggs are adhesive, as are those of many cichlids, and are generally deposited on the underneath of structures. Clutch size varies between 30 to several hundred eggs.

After spawning is completed the male remains beneath the clutch and guards it against intruders. Whilst pursuing these parental duties he is mildly aggressive to other fishes including the female, driving them away from the nest, but never appearing to cause serious damage to tank mates.

The male exhibits a fascinating behavioural response towards the eggs in that he regularly strokes them with the fatty pad on his head, which possibly serves to clean them. Occasionally, the egg clutch disappears and cannibalism by the male and/or female must be suspected. I generally remove the male a few days after spawning. Alternatively, the structure containing the eggs can be moved to a smaller tank, around 2 gallons - a brief exposure to air will not harm the developing embryos.
An aerator stone is positioned near the clutch to ensure good water circulation.

Hatching occurs 5 -12 days later, depending on water temperature. The fry will take their first feed by day 2 post-hatching and will accept finely powdered flake food which can soon be supplemented with newly hatched brine shrimp. Within a month or so the fry can be netted and moved to a larger tank for growing on.

Fatheads live for around two to four years.

Fatheads in the pond (see NOTE below)

Its small size, conspicuous orange colour and active mid-water swimming behaviour ought to make the yellow form of the Fathead an ideal fish for the small garden pond where it would happily co-exist with goldfish. Viewed from above, it resembles a small Golden Orfe.

In Britain, Fatheads would spawn in the pond during the summer months, often depositing their eggs on the undersides of lily leaves. I have maintained specimens outdoors throughout the year although some losses occurred during one severe winter. This apparently poor adaptation to very cold conditions is unexpected, given the fish's extreme northerly distribution; it is possible that the yellow morph is less hardy than the wild fish.

NOTE: The keeping of Fathead Minnows in ponds in GB is illegal.

Legislation under the Import of live Fish Act 1980 (ILFA) prohibits the keeping of some non-native fish in GB, including Fathead Minnows, except under licence.
Defra (or devolved administrations) will not issue licences to keep Fatheads in ponds.

This licensing regulation has resulted in a sharp decrease in Fatheads (and other non-native coldwater species) in the UK trade, but a few hobbyists do keep them, hence they are still obtainable.

To clarify the situation at point of sale, a Centre for Environment, Fisheries & Aquaculture Science (CEFAS) source explains:

'Keeping of Fathead Minnows by hobbyists is only allowed in indoor aquaria.
A general licence has been issued by Defra to allow such keeping, so there is no need for individuals to apply for licences.
Traders wishing to keep Fatheads for sale must however hold an individual licence.
They will be required to maintain records of the numbers of such fish they sell.

Rules for keeping other ILFA species vary from those above.

Red Shiners are subject to the same rules as Fathead Minnows.
Grass Carp, Sturgeon and Ictalurid Catfish are subject to the same licensing conditions but can be kept in enclosed garden ponds.
European Bitterling and Pumpkinseed can only be kept under an individual licence, and have effectively disappeared from trade because retailers are not prepared to check that customers have valid licences, and most hobbyists will not apply for licences.

None of the other ILFA listed species can be legally kept as ornamental animals in GB, as Defra policy is to prohibit such keeping.

The only realistic means to have such ILFA orders work effectively is through good communication, between legislators and the trade and from trade to their customers. The hardest part is keeping very dry legislative requirements in the eye of the general public, or indeed the retail part of trade, but factsheets such as those on the FBAS website, which have direct appeal to fish keepers, prove a much more effective means of communicating the legal position and best practice to end users.'

In conclusion

The yellow variety of the Fathead Minnow deserves to be a favourite for the coldwater enthusiast, especially in view of its fascinating spawning behaviour and general hardiness. So, next time you consider acquiring something unusual for the coldwater tank, think about some Fatheads!


Quinn, J.R. (1990). Our Native Fishes. The Countryman Press Inc., USA.

Reprinted, courtesy of the author, from
the Dunstable & District A.S. NEWSLETTER, May 2006

Last updated September, 2007