Firemouth cichlid

Quick facts

Adult size

15 cm

Lifespan

can live up to 10 years

Tank zone

mid-bottom

Temperament

semi-aggressive

Difficulty

beginner

Water parameters

Temperature

23–28°C

pH

6.5 to 8.0

Hardness

5 to 20 dGH

Tank requirements

Minimum volume

200 L

Minimum length

100 cm

Flow

low

Lighting

any

Substrate

sand

Driftwood

preferred

Hiding spots

needed

Open swimming room

needed

Feeding

Diet: omnivore, feeds primarily at the mid-bottom.

Omnivore that eats anything. Pellets (cichlid-specific sinking or floating), flake, frozen bloodworm, frozen brine shrimp, frozen mysis, live food, and blanched vegetables. They sift through substrate and pick food particles from sand, so sand substrate allows natural feeding behavior. Feed twice daily. A varied diet improves the red coloration on the throat and ventral area. High-quality cichlid pellets with color-enhancing ingredients (astaxanthin, spirulina) make a noticeable difference in display intensity.

Compatibility

• Less genuinely aggressive than its Central American cichlid reputation suggests. The firemouth's threat display (flaring gill covers to show the bright red throat) is largely bluff. Against truly aggressive cichlids like convicts or Jack Dempseys, firemouths usually back down.
• Breeding pairs do become territorial and will defend a zone around their spawning site. The tank needs to be large enough (200 L) that other fish can stay out of the defended area.
• Good tankmates: other medium-sized Central American cichlids of similar temperament (convicts if the tank is big enough, blue acara), larger barbs, rainbowfish, catfish, and larger loaches. Avoid small community fish that would be bullied or eaten.
• The display behavior is the main attraction. Males (and females to a lesser extent) extend their branchiostegal membranes when threatened, revealing the vivid red coloration under the jaw. It's one of the more interesting visual behaviors in the cichlid world.

Habitat

Native to rivers, cenotes, and lagoons of the Yucatan Peninsula, ranging across southern Mexico, Guatemala, Belize, and into Honduras. The species (Thorichthys meeki) was described by Brind in 1918 and named after ichthyologist Seth Eugene Meek. Found in slow-moving to still water over muddy and sandy substrates, often in limestone-influenced habitats with hard, alkaline water. This makes them more tolerant of hard municipal tap water than many South American cichlids. The body is blue-gray with iridescent scales, faint vertical bars, and the signature feature: a bright red-orange coloration covering the throat and extending onto the chest and belly. Males are larger (up to 15 cm), more colorful, and develop longer dorsal and anal fin points than females. The red throat intensifies during breeding and during threat displays. The species has been in the aquarium trade since the 1930s and remains popular because it's colorful, behaviorally interesting, and less destructive than most Central American cichlids of similar size. All stock is commercially bred.

Breeding

Substrate spawner. A pair selects a flat surface (rock, clay pot, driftwood, even the glass bottom) and cleans it meticulously over several days. The female deposits 100-500 adhesive eggs and both parents guard the clutch. Aggression toward tankmates intensifies sharply once eggs are present. Eggs hatch in 3-4 days. Fry become free-swimming after another 4-5 days of absorbing their yolk sacs. Both parents herd the fry in a tight school, with the male patrolling the outer perimeter and the female staying close to the fry cloud. Parental care continues for 3-6 weeks, depending on whether the pair re-spawns. Fry eat baby brine shrimp and crushed flake from the time they're free-swimming. Breeding is easy in a dedicated pair tank with minimal effort. In community setups, fry survival depends on how effectively the parents can defend against tankmates. Pairs in good condition spawn every 4-6 weeks.

Common problems

The bluff-heavy aggression style means firemouths get dominated by genuinely aggressive tankmates. Pairing them with species that call the bluff (large convicts, Jack Dempseys, red devils) results in a stressed, hiding firemouth. Match them with species of similar temperament, not similar size. Hexamita (hole-in-the-head disease) affects firemouths more often than some other Central Americans. The symptoms are pits forming along the lateral line and on the head. Causes are debated but linked to poor diet (especially vitamin and mineral deficiency), chronic stress, and degraded water quality. Metronidazole is the standard treatment. Prevention means a varied diet and clean water. Ich appears in newly purchased fish; standard treatment works. The species is otherwise hardy and long-lived (8-12 years). Territorial fights between two males in a tank that's too small produce lip-locking and jaw damage that can lead to infection.

Bioload

Bioload coefficient: 5.0 (medium cichlid; moderate waste).

Bioload coefficients are calibrated against the neon tetra as the anchor (1.0). See the methodology page for the formula and how each value was derived.

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size