A Guide to Freshwater Fish and Shrimp of the U.S Virgin Islands (Gut Life)

This species is 1 of 5 freshwater shrimp inhabiting tropical streams also known as "guts" in St. Thomas U.S Virgin Islands. This species is diadromous or migratory, spawning in brackish/salt water and leaving the marine environment as juveniles and migrating into freshwater bodies such as creeks, streams and rivers. This species of filter feeder prefers pools with slow trickling water. Species are able to filter feed in pools with low velocity waters. This species varies from a dark brown color to a gray translucent color depending on tannins in the water that occur naturally from leaves and other plant related debris that essentially stains the water. Species turn translucent or gray in clear water. This species is usually really good at camouflaging itself under leaves, twigs and mud in the guts. At times they can be observed clinging to pieces of wood that have entered the pools in the gut. less ↑

Atya innocuous is a rare species in the guts in St. Thomas, U.S Virgin Islands. I believe it is a bio-indicator of water quality. During my M.S research at the University of the Virgin Islands I did not collect very many of this species in surveys. It is 1 or 5 species of shrimp. Atya innocuous resembles Atya lanipes, which is also present in guts in St. Thomas. This species is brown and tan in color, sometimes appearing though it has blotches and sometimes appearing a solid brown color. less ↑

This this species is 1 of 5 freshwater shrimp living in the tropical streams on the island of St. Thomas. These tropical streams are locally called "guts." This species is a predator in the shrimp world and is the largest species of shrimp in the guts on St. Thomas. Macrobrachium carcinus is usually brown and cream in color. M. carcinus is easily identified by its two large claws or pincers. On other island this species have been harvested for food. At one point, this was a food source in the USVI, but the guts are heavily polluted and are no longer considered an edible species. M. carcinus is diadromous, in that it migrates from the marine environment into freshwater bodies like creeks, streams and rivers. less ↑

Xiphocaris elongata also known as the Carrot-nose shrimp or the Yellow rhino shrimp. This species is gray to translucent in color. A gold/yellow line follows from the carapace to the tail on the dorsal side. Nose is also yellow or gold hence the common names. This species is 1 of 3 filter feeder shrimp living in tropical freshwater streams called "guts" on St. Thomas. X. elongata can be observed clinging to rocks or free swimming in the water column in pools in the gut. X. elongata is a herbivore and is non-aggressive shrimp. This species has the ability to climb over barriers reaching pools at high elevations of the gut in St. Thomas. less ↑

Macrobrachium faustinum is 1 of 5 species of freshwater shrimp inhabiting guts in St. Thomas. This migratory species spawns in brackish water or the marine environment. This species has a pelagic life stage before migrating into freshwater bodies as juveniles. This species resembles Macrobrachium carcinus, which also lives in guts in St. Thomas, U.S Virgin Islands. This species is more distinguishable in that it has a claw or pincer that is larger than the other. less ↑

The American Eel is 1 of 7 species of fish living in the guts in St. Thomas, U.S Virgin Islands. This is the only freshwater species of eel inhabiting freshwater gut ecosystems. Anguilla rostrata migrates from the marine environment into freshwater bodies; such as, creeks, streams and rivers. They only leave the freshwater to spawn in the ocean. This species lives in tropical freshwater streams or creeks locally referred to as "guts." This species of eel is declining as result of barriers blocking the migratory paths upstream, habitat loss, and a result of commercial consumption. The iucn redlist has Anguilla rostrata listed as an endangered species. Color patterns vary from olive green, brown, to greenish-yellow with light gray or white on the belly. This species of fish and yes it is a fish is very elusive and usually is not observed free swimming in the guts. They prefer to hide under rocks. less ↑

This species is 1 of 7 freshwater fish living in St. Thomas, U.S Virgin Islands. This species is rare in St. Thomas because it was only collected once during my M.S thesis research at the University of the Virgin Islands. Awaous banana is a larger species of river goby that prefers clear flowing oxygenated waters., but has been previously documented inhabiting muddy/turbid water bodies. Awaous banana is not a predator fish in the gut, but instead is an algae feeder. This species of goby, like Sicydium punctatum has an adapted pelvic fin that allows the fish to cling to rocks at the bottom of streams during high velocity currents. This adapted pelvic fin also allows the species to climb vertically over rocks and over small precipices. This species was observed at my mid- elevation study site, meaning this species had the ability to reach to pools fairly high in the gut. This species was noted as rare in my study and could be a bio-indicator of water quality and/or pollution in guts in St. Thomas, USVI. less ↑

Agonostomus monticola or Mountain mullet is 1 of 7 freshwater fish species inhabiting tropical freshwater streams locally referred to as "guts" in St. Thomas, U.S Virgin Islands. This species inhabits low to mid- elevations. Mountain mullet have the ability to jump and leap, which assists its upstream migration. This species is found in pools below large barriers such as waterfalls or vertical rock precipices that it can not over come. This species of fish is elusive in the guts hiding in crevices and caves in pools in the guts. In the USVI, this species is not considered a sport fish or for food consumption like on other islands. Mountain Mullet are commonly found in tropical freshwater systems with a preference for high-gradient streams with fast-moving waters (Carr and Goin 1955, Cruz 1987). Mountain mullet are olive/gold color on the dorsal side and, white on the ventral side. The dorsal side appears to be gold with dark crisscrossed lines on back. Fins are yellowish/gold. Mountain mullet have a fork tail with a dark blotch on the tail. In the water they appear to be gold and black.

If you enjoyed the guide to freshwater fish and shrimp (Gut Life), please check out my Facebook page below and give it a BIG THUMBS UP. Any comments are always appreciated. Thanks everyone for supporting my research efforts.

You can observe mountain mullet swimming in the guts in a video on my research page: https://www.facebook.com/GutLifeVI/videos/1025747927482841/ less ↑

Gobiomorus dormitor is 1 of 7 freshwater fish on St. Thomas. This species is diadromous or migratory, meaning that this species requires a marine stage before migrating into freshwater bodies as post-larvae (juveniles). This species of sleeper was only collected once in my M.S thesis research at the University of the Virgin Islands. This fish species prefers to sit on the bottom in slow moving waters. It camouflages itself on the bottom in leaves or near logs or woody debris. The Bigmouth sleeper is a carnivore and uses its ambush tactics to feed on insects, other invertebrates and other fish. This species is light to dark brown with a lighter white belly (ventral side). less ↑

Eleotris picta or the spotted sleeper is slowing benthic lurking fish. It hides among the leaves or blending in with logs or woody debris sunken under the water. These species of fish waits to ambush prey. In the gut, these fish are very difficult to spot due to their ability to camouflage themselves really well. The spotted sleeper is a carnivore consuming insects, invertebrates and other fish. Color patterns of E. picta vary depending on tannins in their environment. These species are usually a dark brown with a lighter brown dorsal side and darker brown on their sides near the pectoral fins. The coloration is very cryptic which is a super advantage to this species when avoiding predators and hunting its own prey. This species becomes lighter in color in clear water; such as a fish tank with no tannins being introduced from leaves, mud or vegetation. Fins are arm-like. In the guts, I would consider this a predator fish species. E. picta do have teeth. less ↑

Sicydium punctatum is 1 of 7 species of freshwater fish living in gut habitats. This smaller stream goby is commonly called the spotted algae-eating goby or the green stream goby coined after its remarkable color patterns. This species is quite unique as it has the ability to climb over barriers such as vertical slope precipices or waterfalls as long as some degree of trickling flow persists. S. punctatum has the ability to exhibit a variety of colors. This most likely depends on sex and age. This species is a herbivore feeding on algae off rocks on the bottom of the guts. Approaching the gut these species of fish appear to swim off frantically. Depending on the time of year and location, you may able to observe the spotted algae-eating goby due to its iridescent blue-green color. This is the only fish species present in pools at higher elevations in the mountains of St . Thomas and St. John, U.S Virgin Islands. Other fish do not have the same adapted physical characteristics that allow them to overcome obstacles during upstream migration. This species is quite unique and common in the guts.

If you enjoyed the guide to freshwater fish and shrimp (Gut Life), please check out my Facebook page below and give it a BIG THUMBS UP. Any comments are always appreciated. Thanks everyone for supporting my research efforts.

You can observe Sicydium punctatum swimming in the guts in a video on my research page: https://www.facebook.com/GutLifeVI/videos/1025747927482841/ less ↑

Poecilia reticulata or the common guppy is 1 of 7 species of freshwater fish inhabiting guts on St. Thomas, U.S Virgin Islands. It is quite common because of its ability to reproduce rather quickly. It inhabits drainage ditches, ponds, and guts. Poecilia reticulata is an introduced species and is not native to the guts. It is believed to be introduced via aquarium as a discarded pet. This species also could have been introduced for mosquito control as it is commonly called the mosquito-fish. This species of fish was only collected in one area (e.g. near a bridge) in the Dorothea Gut for the duration of my M.S thesis research at the University of the Virgin Islands. Males are known for their more vibrant colors and flashy tails. This species is not diadromous or migratory like the other 6 species of fish native to the guts. This species is a live-bearer meaning no eggs. They have been called the million-fish for this exact reason..they have the ability to have large numbers of live young. less ↑