Firemouth cichlid

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: sand.

Behavior

Plant interaction: digs up plants.

Feeding

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 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 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.

Origin and habitat

Native to Central America's Atlantic slope from the Rio Tonalá system near Coatzacoalcos, Mexico, through Veracruz, Chiapas, Tabasco, around the Yucatan Peninsula, and south into northern Belize and Guatemala. Naturalized in Hawaii (since 1940) and Puerto Rico. Described by Walter Brind in 1918 as a subspecies of T. helleri. Named after Seth Eugene Meek (1859-1914), who compiled the first book on Mexican freshwater fishes. The genus name Thorichthys combines Greek thrōiskō ("to leap, spring") and ichthys ("fish"), describing the fish's behavior of leaping at objects entering the water. Body is grey to yellow-olive with five to six dark vertical bars, red-edged fins dotted with blue spots, and the signature bright orange-red coloration on the throat and gill covers. This ventral color becomes vivid during the species' famous threat display: males flare their gill covers wide, exposing the red throat and making the fish appear much larger. The display is primarily bluff. Max total length about 17 cm; females smaller at up to 8 cm SL. Found in slow-moving to still water: rivers, cenotes, ponds, and canals with sandy and muddy bottoms. Primarily a benthic omnivore that sifts substrate for detritus, mollusks, copepods, and insects.

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 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

Further reading

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