Therefore, F. grandis is among the largest minnows preyed upon by many sport fish, such as flounder, speckled trout (Cynoscion nebulosus), and red drum (Sciaenops ocellatus).
This is significant to conservation biology, because with the continued extraction of oil and other natural resources from North American waters, it has become increasingly important to understand the risks and consequences in worst-case scenarios, such as the Deepwater Horizon oil spill, and the lasting effects on the marine ecosystem.
[13] The anterior edge of a gill slit is motile, moving outward to allow water to exit, but closing to prevent reverse flow.
[14] These different habitats include estuarine, lowland, upland, coastal marshes, lagoons, rivers, and streams.
[14] Spending a lot of time near the coasts ensures that the Gulf killifish is able to survive various salinity ranges including fresh water because their habitats get influx of freshwater into the ecosystems normally.
[18] Gulf killifish develop an early ability to osmoregulate because they are born with functional gills and mature mouthparts.
[19] Lower water temperature with the use of shade in June, July, and August lead to the highest number and most viable eggs.
[20] Another key characteristic of the habitats, which is influential to the survival of Gulf killifish, is the amount of dissolved oxygen.
[21] Lower levels of oxygen is common in near-shore environments, one of the main habitats of the Gulf killifish.
[21] One main threat because it decreases the levels of dissolved oxygen is the Louisiana dead zone, which kills large numbers of fish every year.
[22] This dead zone results from nutrient- and chemical-rich water from the Mississippi River Valley basin entering the Gulf of Mexico.
This eutrophic water ultimately leads to no dissolved oxygen remaining within the ecosystem because of increased activities of algae and decomposers.
[22] Fish collected during the summer were better suited to hypoxic conditions because they were already acclimated to the lower levels of dissolved oxygen more so then than any other season.
[21] F. grandis is an egg-laying fish, and uses the soft muddy bottoms of saltwater or brackish ecosystems to lay eggs.
The egg's shell is sensitive to dissolved oxygen and carbon dioxide present within the water that can initiate hatching.
[25] This internal form of evolution is compromised when anthropomorphic effects disrupt the aquatic ecology in which they are laid.
These substances can then begin to affect the biochemical morphology of the developing embryos or newly hatched larvae, leading to underdeveloped cardiovascular systems, decreased nerve functions, decreased endocrine and hormone secretions, and reduced gill tissue development.
Females may also grow 5–8 cm larger than the males and may exhibit more aggressive behaviors during the mating season.
Once fully grown, F. grandis adults are omnivorous, feeding on algae and vascular plants, small grass shrimps (Palaemonetes), microcrustaceans (copepods), and mosquito larvae.
[citation needed] The Gulf killifish plays an important role in scientific research concerning the disaster resulting from the Deepwater Horizon oil spill.
[31] The spill affected the Gulf coast area about a year and was finally determined to be maintained in October 2011.