Max Size: 7cm

Merry Widow Livebearer (Phallichthys amates)

The Merry Widow is a somewhat rare, peaceful and lively fish perfect for a community aquarium. These fish are very hardy with great personalities, making them ideal for the beginner aquarist. These livebearers know what is happening around their home aquarium and beg for food from their owner while often ignoring other humans approaching the tank.

Ideal tankmates for Merry Widows could include Corydoras Catfish, Plecos, Livebearer and smaller Central American Cichlids. In addition, Barbs, Rainbowfish, Tetras and Gouramis can also make excellent tankmates. However, it would help if you kept in mind that when housing these fish with most of these species, Merry Widows are unlikely to have any fry survive more than a few days, as the other inhabitants will probably consume them.

Merry Widows are best kept in a group of 6 or more individuals, ensuring you have two females to every male, as this will stop any single female from taking the full brunt of the male's continual harassment.

The ideal aquarium setup for these fish would incorporate plenty of hiding places amongst thick planting from both rooted and floating types. Not only will this help your fish feel more secure, but it will also allow them to show their best colours and make your aquarium aesthetically pleasing whilst protecting any fry. The aquarium will need to be somewhat spacious as these are very active fish and will need good filtration.

Merry Widows have a greyish-silver body colour with a bluish sheen. Both the male and female are marked with 6 to 8 dark vertical bars on their body. These fish have a dorsal fin marked with two arcs parallel to the outside edge; both arches are dark, but the inner one is slightly lighter. In addition, they also display a short black line that runs through the eye to the throat, and their gill covers reflect an iridescent bluish-green.

Quick Facts
Scientific NamePhallichthys amates
Year Described1907
Other NamesMerry Widow
OriginsCosta Rica, Guatemala, Honduras, Nicaragua, Panama
Aquarium LevelAll Levels
Best kept asGroups 6+
Lifespan3 - 5 years
Water Parameters
Water TypeFreshwater
PH6.0 - 8.0
GH5 - 20
KH2 - 6
TDS60 - 150
75 - 80℉
23.9 - 26.7℃


Merry Widow Livebearer
Merry Widow Livebearer

Natural Habitat

Merry Widows are endemic to the Rio Montagua in Guatemala, the Rio Reventazon in Costa Rica, and the Rio Chagres in Panama. You can also find this species in Honduras and Nicaragua in Central America. These fish inhabit slow-flowing waters in creeks and streams as well as other backwaters and stagnant areas. Their habitats usually contain muddy substrates and aquatic vegetation.

Chagres River
Reventazón River
Motagua River


In the wild, Merry Widows primarily graze on algae and microfauna that grow on surfaces in the stream, as well as the occasional crustacean and insect. These fish are not fussy eaters in the aquarium and will take high-quality dried foods like flakes and pellets alongside live, frozen and freeze-dried foods. You will also notice these fish nibbling on surfaces in the aquarium, likely consuming the available biofilm between meals.

Sexual Dimorphism

It is relatively simple to differentiate between the male and female Merry Widow. The females are much larger and have slightly duller colouring than the males. In contrast, males have a very long gonopodium that can reach the base of the tail, and they have a smaller, more slender body than females.


Merry Widows are easy to breed and are prolific breeders. These fish have a gestation period of approximately 28 days, depending on water temperature. The female can give birth to between 10 and 80 babies depending on their age.

It would be best if your aquarium were heavily planted, as this will increase the survival rate of the fry; if this isn't possible, then you can place the fry in a breeding box to develop. The fry will be able to take crushed flake food, baby brine shrimp and microworms as soon as they are born and can eat the same food as the adults shortly after that.

Other Livebearers of interest

Cardinal Brachyrhaphis(Brachyrhaphis roseni)
Dusky Millions Fish(Phalloceros caudimaculatus)
Humpbacked Limia(Limia nigrofasciata)
Mollies(Poecilia Sphenops)
Platies(Xiphophorus maculatus, Xiphophorus variatus)
Spotted Skiffia Multipunctata(Skiffia Multipunctata)
View all Livebearers
Date Added: 13/06/2022 10:13:20 - Updated: 13/06/2022 13:18:40