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Ceriodaphnia dubia are very small, never larger than one millimeter in length.  When in good health, they appear to be a brownish-orange color.  There is a large, dark spot on the anterior end of every Ceriodaphnia, this is the compound eye.  Males and females can be distinguished from each other by their shape and size.  Males are smaller and less rotund than are the females; the males are almost triangular in shape.  Movement is achieved by a powerful set of second antennae.  Because of this, movement is generally vertical and jerky.

Daphnia magna are similar to Ceriodaphnia dubia but larger, usually five to six millimeters in length.

Adult mysids range in length from 4.4 mm to 9.4 mm.  Living mysids are usually transparent, but may be tinted yellow, brown, or black.  Females are usually larger than males, and sex can be determined when a body length reaches 4 mm. 

Adult fathead minnows are small in size and can range from 43 to 102 millimeters in length, although the average length is 50 millimeters.  Mature males have nuptial tubercles and an elongate pad extending in a narrow line from the nape to the dorsal fin.  The sides of the bodies of males become almost black except for two wide vertical bands which are light in color.  The females are drab in comparison.

Adult Menidia beryllina attain a total length of up to 117 mm.  Females are generally slightly larger than males.