Freshwater

Argentine pearlfish

Austrolebias bellottii

The Argentine pearlfish has a laterally compressed, fusiform (spindle-shaped) body with a rounded profile. Males are …

Black Molly

Poecilia sphenops

The Black Molly has an elongated body. Females tend to be more rounded in appearance. The …

Constancia’s seasonal killifish

Cynolebias constanciae

The body of Constancia's seasonal killifish (Cynolebias constanciae) is elongate and slightly laterally compressed.

Eastern mosquitofish

Gambusia holbrooki

The body of the Eastern mosquitofish is moderately elongated, not tall, and laterally compressed. It is …

Finescaled four-eyed fish

Anableps microlepis

Anableps: Greek, ana = up + Greek, blepo, blepsis, -eos = glance, sight.The elongated cylindrical body …

Green swordtail

Xiphophorus hellerii

Green swordtails have elongated, narrow bodies that are flattened on the sides. They also have large …

Guppy

Poecilia reticulata

Guppies exhibit pronounced sexual dimorphism, with males and females differing in size, shape, and colouration. Males …

Least killifish

Heterandria formosa

Least killifish differ little in body shape from their closest relatives, the Poecilia. They have an …

Mosquitofish

Gambusia affinis affinis

The male anal fin is modified and is an intermittent organ for introducing sperm into the …

Paddlefish

Polyodon spathula

The paddlefish is almost sharklike in appearance, and if you cut off its long paddle-like snout, …

Pallid sturgeon

Scaphirhynchus albus

The pallid sturgeon has a distinctive, prehistoric appearance. Its body is elongated, nearly cylindrical, with a …

Porous seasonal killifish

Cynolebias porosus

The Porous seasonal killifish has a fusiform (spindle-shaped) body that is laterally compressed. The snout is …

Siberian sturgeon

Huso baerii

The Siberian sturgeon has a spindle-shaped body with several longitudinal rows of bumps. Its short, triangular …

Sturgeon, Atlantic

Acipenser oxyrinchus

The Atlantic sturgeon is dark brown or olive green with a white belly. The head is …

Sturgeon, Lake

Acipenser fulvescens

Lake sturgeon are somewhat torpedo-shaped, and the upper lobe of the caudal fin is longer than …

Sturgeon, Shovelnose

Scaphirhynchus platorinchus

The shovelnose sturgeon has a broad, flat head with an elongated shovel-like snout. There are four …

Sturgeon, White

Acipenser transmontanus

The adult white sturgeon has a moderately blunt snout, spines closer to the tip of the …

Sturgeon: Green Sturgeon

Acipenser medirostris

Sturgeon and paddlefish, best known for their black caviar, belong to the order Acipenseriformes, but at …