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FishbeginnerFreshwater

Black Lyretail Molly

Poecilia sphenops

AnimaliaChordataActinopterygii

Variety of Molly · black lyretail

📍 Mexico

Ask Finn

A doubly selected variety combining solid jet-black coloration with an elegant, elongated lyretail fin shape where the upper and lower rays extend into points. Hardy and adaptable like standard mollies, it benefits from slightly brackish water and a diet supplemented with algae.

Size3"
Min Tank20g
School3+
peaceful
Zonemid

Care Guide

Diet

Black Lyretail Mollies are omnivorous and should receive high-quality flake food or pellets as a staple, supplemented 2-3 times weekly with blanched vegetables like spinach, zucchini, and algae wafers. They benefit from occasional frozen foods such as brine shrimp or daphnia. Feed small amounts once daily, only what they can consume in 2-3 minutes.

Behavior

These peaceful, active fish are strong swimmers that prefer the mid-water column and spend much of their day grazing and exploring. They are social and should be kept in groups of at least 3 to reduce stress and encourage natural schooling behavior. Males may display mild territorial behavior toward each other, but aggression is minimal compared to other molly varieties.

Breeding

Black Lyretail Mollies are livebearers that breed readily in captivity with minimal intervention; females produce 20-100 fry every 4-6 weeks once mature. Provide dense vegetation or breeding boxes to protect fry from predation by adults. Breeding is easy but population control may be necessary in established tanks.

Common Diseases

Fin Rot

Symptoms

Frayed, disintegrating fins; white or black edges on fin margins; lethargy

Treatment

Perform 25% water changes every 2-3 days, improve water quality, and treat with aquarium salt (1 tsp per gallon) or antibacterial medication if severe

Ich (White Spot Disease)

Symptoms

White spots covering body and fins; excessive scratching against objects; rapid breathing

Treatment

Raise temperature gradually to 28-30°C (82-86°F), perform daily water changes, and treat with ich medication or aquarium salt for 7-10 days

Velvet Disease

Symptoms

Fine golden or rust-colored dust on body; clamped fins; loss of appetite; rapid gill movement

Treatment

Darken the tank, raise temperature to 28°C (82°F), and treat with copper-based medication or methylene blue following product instructions

Dropsy

Symptoms

Bloated abdomen; scales standing out like a pinecone; lethargy; loss of appetite

Treatment

Isolate affected fish, perform frequent water changes, feed high-quality foods, and treat with antibiotics if bacterial; prognosis is often poor

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Water it likes

ph
7.0–8.5
ammonia
0 ppm
nitrate
<20 ppm
temperature
70–82°F (21–28°C)

Stats

Community tips0
Kept by0 hobbyists