Species description

Care, breeding and tankmates

Fish profile

Temperament

Active

The Mummichog is a bold, highly active, and sometimes pugnacious fish that is never shy. They are constantly on the move and will eagerly approach the front of the glass when they see their keeper. They are incredibly tough fish, famously capable of surviving in extreme environmental conditions.

Diet

Omnivore

They are omnivorous and highly opportunistic feeders in the wild, consuming everything from algae to insects and small crustaceans. In the aquarium, they are unfussy and will eagerly accept flakes, pellets, frozen foods, and live foods. A varied diet that includes both meaty foods and plant matter ensures optimal health.

Sex ratio

Group

Males are typically more colorful, especially during breeding season when they display bright yellow bellies and silver bars, while females are plumper and more subdued. They are best kept in a mixed group with a ratio of one male to two or three females. This reduces male aggression and prevents harassment of individual females.

Feeding frequency

Twice daily

Being very active, they have hearty appetites and benefit from being fed one to two times a day. They are aggressive eaters that will rush to the surface at feeding time. Care should be taken not to overfeed, as their begging behavior can be persuasive.

Bioload

Medium

The Mummichog is an extremely hardy, medium-sized killifish that produces a moderate bioload. They are enthusiastic eaters that generate a fair amount of waste for their size. Robust filtration and regular water changes are recommended, although they are famously tolerant of poor water quality.

Flow

Strong

Originating from tidal salt marshes and estuaries, they appreciate a moderate to strong water flow. Good water movement helps simulate the changing tides of their natural habitat and keeps them active. However, they are incredibly adaptable and can also thrive in still water conditions.

Jump risk

Yes

Like most surface-dwelling killifish, Mummichogs are excellent jumpers, especially when startled or chasing prey. A tight-fitting lid is absolutely required to prevent them from ending up on the floor. Be cautious during maintenance, as they may attempt to jump out when the lid is removed.

Reproduction

Oviparous

Breeding is easy, as they are prolific spawners in captivity. They lay sticky eggs in vegetation or spawning mops, often corresponding with the lunar cycle and tidal changes in nature. The eggs are hardy, and the fry are large enough to take newly hatched brine shrimp immediately after hatching.

Compatibility & tankmates

Community

They are generally peaceful but highly active and somewhat boisterous. They can be kept with other robust, similar-sized fish that tolerate brackish conditions, such as mollies or gobies. They may nip the fins of slow-moving or long-finned fish, and very small tank mates might be harassed.

Tank level

All levels

They primarily inhabit the middle and upper levels of the water column. They are constantly swimming and exploring, often patrolling the water surface for fallen insects. They require plenty of open swimming space alongside areas of dense vegetation.