List of Fish Species in the Salton Sea (Updated)

Once a thriving tourist destination, an oasis for migratory birds in the California Desert, and a source of life-sustaining water for critical agricultural projects, the Salton Sea is currently little more than a dwindling, increasingly saline pool of disease and tilapia. The peculiar history of the Salton Sea follows a series of floods and droughts leading to the creation of one of the United States’ most inhospitable lakes.

Throughout history, the Colorado River would intermittently drain into the Salton Sea, filling it during some periods and leaving it to dry out during others but, in the early 1900s, farmers dug an irrigation canal from the Colorado River to the Salton Sea to permanently prevent it from naturally evaporating. In the mid-1950s, the Salton Sea became a resort and attracted tourists from all over the country.

With no outlet, salt, agricultural runoff, and disease became concentrated in the lake towards the end of the 20^th century. Avian botulism, cholera, and salmonellosis plagued resident and migratory birds that used the lake, regularly resulting in the death of thousands of birds even in the modern day. In addition, the Salton Sea has a salinity of around 60 parts per thousand, close to double the average salinity of the ocean. As a result, few species of fish can survive in the lake, and most of the aquatic biodiversity in the area occurs in disconnected pools of freshwater around the lake.

Despite the ongoing ecological disaster, hope is not lost for the Salton Sea. Several organizations, like the Salton Sea Authority and the Species Conservation Habitat project, aim to restore the lake to a thriving oasis. Projects focus on constructing wetlands to filter pollution from what little water enters the lake, importing freshwater, and reducing the number of exposed lakebeds.

1) Mozambique tilapia (Oreochromis mossambicus)

One of the few inhabitants of the Salton Sea is a sunfish look-alike known as the Mozambique tilapia. The common name “tilapia” refers to a handful of cichlid groups that are typically important food fish for cultures around the world. Additionally, these species are sometimes kept as pets in the aquarium trade. Cichlids can be easily distinguished from sunfish by looking at the number of nostrils. Sunfish have two, while cichlids have one. Mozambique cichlids are dark-colored fish with a somewhat rusty-colored pectoral fin. In addition, most individuals have an underbelly with a light color that travels into their cheeks.

Mozambique cichlids have found their way to the United States for several reasons, from intentional introductions as biological control agents for weeds and insects to sportfish stock and aquarium releases. They are known to be hardy with a high reproductive rate, an aggressive nature, and tolerance for high salinity. This last trait allows the Mozambique cichlid to thrive in the saline waters of the Salton Sea, where predators cannot survive.

While invasive in the United States, the Mozambique tilapia is somewhat imperiled in its native range. Considered vulnerable to extinction by the IUCN, this species is a poor competitor to other invasive tilapia species that found their way into its native range in southern Africa.

2) Redbelly tilapia (Coptodon zillii)

Another salinity-tolerant cichlid present in the Salton Sea is the redbelly tilapia. This species is a light green to olive color with a striking red belly. Some individuals also possess vibrant blue chins and iridescent spots on their fins. Redbelly tilapia also grow considerably, regularly reaching lengths of more than 12 inches (30 cm). This species constructs nests during the breeding season and aggressively defends its eggs, much like sunfish.

They are usually active during the day, forming schools while they search for prey items consisting of vegetation and insects. As a result, the redbelly tilapia was introduced to the Salton Sea to control invasive plants and aquatic insects. Additionally, some individuals have been released illegally from aquariums. They are remarkably tolerant of saline waters and thrive in warm water; the Salton Sea has both characteristics making it the perfect habitat for this species.

Even though tilapias are edible, the tilapia found in the Salton Sea are likely teeming with disease-causing bacteria and toxins and should not be consumed.

3) Wami tilapia (Oreochromis urolepis)

Mozambique tilapia also often hybridize with another tilapia species known as the Wami tilapia. This cichlid is usually a dull, dark color with some rusty colors on the dorsal and caudal fin. They are also medium to large-sized fish with a maximum length of 17 inches (43 cm). They were initially introduced to the Salton Sea to control populations of nuisance aquatic plants and insects like mosquitos. This effort is reportedly highly successful.

This species employs an odd reproductive strategy called mouthbrooding, wherein adult females will hold eggs and larvae in their mouths. Young fish seek refuge in their parents’ mouths when predators are nearby. In Wami tilapia, the female usually takes on this responsibility.

Like the other two tilapia species on this list, Wami tilapia are salt-tolerant and are one of the few species that can survive in the harsh Salton Sea.

4) Western mosquitofish (Gambusia affinis)

The western mosquitofish can be found throughout most United States’ waters. It thrives in diverse habitat types and is tolerant to adverse conditions like pollution, low oxygen, and temperature fluctuations. They have been observed in or near the Salton Sea as recently as 2020. On average, they are around 2.7 inches (7 cm) in length.

This species has an omnivorous diet consisting of insects, insect larvae, zooplankton, and algae. They reproduce from April to September. During this time, males put on a display to attract a female. After mating, the embryos develop within the females, and then the females give live birth. They can reproduce multiple times during the breeding season leading to a rapid increase in population. Western mosquitofish are short-lived however, rarely living past 15 months.

They are used as mosquito control in some areas to prevent the spread of infectious diseases, although their efficacy as biocontrol agents is debated. In some areas of the western United States where they have been intentionally or unintentionally introduced, mosquitofish have contributed to the decline of native species that occupy the same niche, such as the Railroad Valley springfish (Crenichthys nevadae).

5) European carp (Cyprinus carpio)

The European carp has been observed in the Salton Sea drainage as recently as 2022. Historically, they were extraordinarily abundant but have since become overtaken by tilapia in numbers due to the declining habitat quality of the lake.

The European carp is one of the most disastrous fish introduced to the United States. This species is omnivorous, consuming both plants and small invertebrates. In search of food, it digs up gravel beds and uproots native plants, converting otherwise clear streams into murky messes that are unsuitable habitats for many native species. Habitat conversion disrupts local ecosystems by destroying habitats and eliminating food sources for native species. In addition to being an ecological nuisance, the European carp is considered a sportfishing pest.

6) Desert pupfish (Cyprinodon macularius)

The imperiled desert pupfish is possibly the only native fish that could survive in the Salton Sea. This small fish resembles a livebearer; while they are related, they are in different families. On average, desert pupfish are less than 2 inches (5 cm) long. They are very salt-tolerant, and the Salton Sea is one of the few places where this species still naturally occurs. Their primary food sources include insects, invertebrates, and aquatic vegetation. Desert pupfish are known to be an effective form of mosquito control in some areas because they eat mosquito larvae.

Male pupfish are usually ornately colored with silver and a blue sheen. Their dorsal fins are also tinted with orange. Females, on the other hand, are silver with brown splotches. During the mating season, males will attempt to “dance” with females during courtship.

The desert pupfish is classified as vulnerable to extinction by the IUCN, and several factors influence their population decline. The primary threats to desert pupfish in the Salton Sea include increasingly hazardous water conditions and competition with and predation by invasive tilapia like the redbelly and Mozambique tilapia.

7) Red shiner (Cyprinella lutrensis)

Ubiquitous throughout much of the United States, the red shiner is highly tolerant of changes in water quality, particularly turbidity, and can be found in most rivers and streams. Due to their tolerant nature, they effectively invade novel ecosystems and sometimes compete with native fish species.

The red shiner is a small, silvery blue fish with red fins. A typical red shiner will be about 2 inches (5 cm) long. They primarily feed on insects and algae and are prey items for many larger fish species. Interestingly, because sunfish predate heavily upon small fish, in this case, red shiner juveniles, the presence of sunfish, be they native or non-native, may reduce the overall threat of invasive red shiners in novel ecosystems.

8) Bairdiella (Bairdiella icistia)

Another perch relative that may be found in the Salton Sea is the bairdiella. Bairdiellas are demersal fish, spending most of their time near the bottom of water bodies. They are similar in appearance to the orangemouth corvina but can be distinguished from them by observing the length of the anal spine. In bairdiella, the spine is longer than the fin rays, whereas in orangemouth corvina, it’s the opposite. Baridiellas are also smaller than orangemouth corvinas, approximately 8 inches (20 cm) on average.

This species was introduced to the Salton Sea as a sportfish with an initial stocking size of 57 fish in 1950. The species’ populations increased three years later, and millions of fish populated the lake.

The fate of the bairdiella is intertwined with the survival of the pileworm, a salt-tolerant nereid worm that spends most of its time in the substrate. Despite their salt tolerance, their ability to reproduce is hindered when salinity levels exceed 45 ppt. Bairdiella exclusively predates upon this worm, so if worm populations decline, so do bairdiella populations.

9) Orangemouth corvina (Cynoscion xanthulus)

This large perch relative was introduced in California and Texas as a sportfish. They are silver fish with orange-tinted fins and a striking orange mouth, giving them their common name. Orangemouth corvina, also known as orangemouth weakfish, can grow to impressive sizes with a maximum length of around 35 inches (90 cm) and a weight of 54 lbs (24 kg). As a result, they are popular among anglers despite not being the best fish for eating.

In the Salton Sea, orangemouth corvina spawn during the summer, although very little is known about the reproductive strategies of this species. Presumably, they reproduce like other Cynoscion species by using audible “croaks” to attract a mate and broadcasting their eggs across the substrate, providing no parental care.

As the toxicity of the Salton Sea becomes more severe, orangemouth corvina populations are declining and will eventually become extirpated from the area.