Bromeliads comprise an entire order of flowering plants called Bromeliales. The pineapple is the most familiar member of this tropical American group, which also includes some of the most interesting plants of the rainforest—the tank bromeliads.

Most bromeliads are epiphytes—that is, plants that live attached to other vegetation. Many live high above the forest floor, deriving energy from photosynthesis, water from rain, and nutrients mainly from falling debris and windblown dust.

The tank bromeliads have relationships with a wide variety of other organisms. The water held in the leaf rosette of a tank bromeliad forms a virtual aquarium, which may contain up to 20 litres (5 gallons) of water. Several hundred species of aquatic organisms can be found in these habitats, and some are found nowhere else except in bromeliad pools.

Among the creatures found here are fungi, algae, protozoa, and small invertebrates such as insects, spiders, scorpions, mites, worms, and even crabs. Vertebrate inhabitants of bromeliad tanks include frogs, salamanders, and snakes. Animal life, however, is dominated by insects, especially dipterans (two-winged flies) such as nonbiting midges and mosquitoes. On occasion, an aquatic species of bladderwort can be found floating in bromeliad tanks.

source: here