Texas cichlid

The cichlid is known for its complex reproductive behavior with a long parental care period. The mating habits of the cichlid are tied to the monogamous nature of the fish. The competitive pairs always consist of a larger male and a smaller female.[6] These pairs travel long distances between the months of March and August to mate and aggressively defend their mating sites against other pairs of cichlids.[5][7]

Prior to spawning, a site, generally consisting of rocks in water less than 30 cm deep, is chosen by both parents and cleaned by nipping the surface. No individual cichlid appears to maintain territory prior to mating. After a territory is selected and cleaned, the eggs are deposited.[6]

Females release between 1-5 eggs at a time.[8] Males then go to the eggs and excrete a seminal fluid onto the egg. This process is repeated until around 2,000 eggs have been distributed.[8] During the egg stage, both parents alternate in the parental tasks, though males spend more time patrolling territory and females spend more time actively attending to the offspring by fanning the eggs. At certain intervals, the female cichlid stops fanning the eggs and begins nipping at them. The eggs then hatch into wrigglers with yolk sacks which are absorbed after one week and the wrigglers become free-swimming fry.[6]

The fry form a small group that slowly moves around the territory with the parents stationed in the middle. Both parents defend this small territory against intruders. At all stages, the female violently chases the intruders more often and faster than the male parent. It is very rare that both cichlid parents either leave or remain with their young. Typically, the roles are exchanged, but this exchange becomes less frequent during the fry stage as both parents tend to stay with the young.[6]

In Florida, the success of the fish has been limited to artificial canals.[5] It is unknown how the fish first got into Florida, but it is believed that the fish was introduced in Florida from Texas stocks in 1941 by a private individual. Other theories are that fish farms were flooded and the result was that this fish escaped.[11]

In Louisiana, the fish has slowly taken over the waters of New Orleans. The fish has a high salinity tolerance (up to 8 ppt), but it is likely that this is caused by the interbreeding of this fish and the related lowland cichlid (Herichthys carpintis), which makes it an ideal invader for the brackish conditions of southern Louisiana.[5] It is believed that this fish has entered into the New Orleans area through multiple aquarium releases in central Jefferson Parish in 1989. Since the fish has a short mating cycle, it did not take long for the fish to make its way through the canal system and into Lake Pontchartrain.[12] Pump stations and Lake Pontchartrain aided to the spreading of the fish into other canals.

Herichthys cyanoguttatus has been present in natural and degraded habitats of the Greater New Orleans Metropolitan Area for at least 20 years. The first time it was ever recorded that the cichlid had been caught in New Orleans was on 17 June 1996. In May 1998, 23 fish were caught in a Jefferson Parish canal. Between 2006 and 2007, the number of cichlids increased significantly in sites such as Pontchartrain Lagoon, Bayou Metairie, and Marconi Lagoon. The effect of the invasive fish in the area is as of now, uncertain, but many studies have been done to figure out what exactly is going on.[5]

Some of these studies have shown that this cichlid has spread into Bayou St. John and City Park. The cichlid acts aggressively toward native Largemouth bass, Western mosquitofish, sailfin mollies, and blue crabs. This aggressiveness can occur in the form of tail beating and mouth wrestling.[13] The fish also appears to cause reproductive failure of sheepshead minnows.

The Texas cichlid was largely unaffected by abiotic events like Hurricanes Katrina and Rita because of its high tolerance for salt-water intake.[5] In fact, these hurricanes actually helped the fish to take over the bayous of New Orleans. When the park flooded during Katrina, it helped the cichlid to spread.[14]

In Bayou St. John, the cichlid threatens to overwhelm native species and ruin the efforts of the Louisiana Department of Wildlife and Fisheries to restore the historical fishery of Bayou St. John. Because the fish competes with native fish for shallow mating sites, it reduces the chances of the diverse fishery ever being fully recovered.[15]

The fish has already eliminated several smaller fish in this bayou, including killifish and sheepshead minnows. In fact, if the Louisiana Department of Wildlife and Fisheries did not routinely re-stock several midsized species, it is likely that the cichlid would have eliminated these fish too.[7] Because of this, there is even a competition at the "City Park Big Bass Fishing Rodeo & Fishtival". to catch the most cichlids. According to a fisherman Joe Adams, who participates in the competition,

"They will eat just about anything ... I know one guy who catches them with French fries ... pieces of a hot dog and pieces of canned corn."

Despite these efforts, there is practically no chance of eradicating this fish from New Orleans' waters, mainly because of its quick mating cycle.[7]