Bottom feeder

A cory catfish, a commonly kept bottom feeder species in freshwater aquaria.

A bottom feeder is usually an aquatic animal that feeds on or near the bottom of a body of water.^[1] The body of water could be the ocean, a lake, a river, or an aquarium. Bottom feeder is a general term which is used particularly in the context of aquariums. Biologists often use the term benthos, particularly for invertebrates such as shellfish, crabs, crayfish, sea anemones, starfish, snails, bristleworms and sea cucumbers. However the term benthos includes all aquatic life that lives on or near the bottom, which means it also includes non-animals, such as plants and algae.

Biologists also use specific terms that refer to bottom feeding fish, such as demersal fish, groundfish, benthic fish and benthopelagic fish. Examples of bottom feeding fish species groups are flatfish (halibut, flounder, plaice, sole), eels, cod, haddock, bass, grouper, carp, bream (snapper) and some species of catfish and shark.

Biological trends

Bottom feeders are not necessarily detritivores, although there are many that are. Some bottom feeders graze along the bottom, feeding on plant material. Other bottom feeders may feed on other bottom feeders, and thus are carnivores.

Many bottom feeders are also capable of burying themselves. A variety of invertebrates are able to bury themselves, such as bristleworms, sea cucumbers, and snails. Many vertebrate bottom feeders may bury themselves, such as flatfish or stingray.

In many bottom feeders, a mechanism to deal with substrate is often necessary. In the case of some organisms such as sea cucumbers, the sand is usually passed through the body. In fish, sand will be pumped out of the mouth through the gill slit.

In fish, most bottom feeders exhibit a flat ventral region so as to more easily rest their body on the substrate. The exception may be the flatfish, which are laterally depressed but lie on their sides. Also, many exhibit what is termed an "inferior" mouth, which means that the mouth is pointed downwards; this is beneficial as their food is often going to be below them in the substrate. Those bottom feeders with upward-pointing mouths, such as stargazers, tend to seize swimming prey. Some flatfish such as halibut actually have a "migrating" eye that moves to the upward-facing side of the fish as it ages.

In 2014, it was reported that deep sea bottom feeders absorb carbon dioxide by eating creatures such as jellyfish and cephalopods, allowing the gas to be contained at the sea floor rather than be recycled back into the atmosphere.^[2]

Aquarium care

In the aquarium, bottom feeders are popular as it is perceived that they will clean the algae that grows in the tank. Generally, they are only useful for consuming the extra (fresh) food left by overfed or clumsy livestock; the added biomass of additional organisms means that the aquarium will likely be more dirty. Some specialized bottom feeders are more specifically sold as "algae eaters" to increase the amount of free oxygen and aesthetic appeal of a tank.

See also

• Demersal fish
• Groundfish
• Whitefish (fisheries term)

References

Feeding behaviours
Carnivores	adult Hematophagy Insectivore Lepidophagy Man-eater Molluscivore Mucophagy Myrmecophagy Ophiophagy Piscivore Avivore Spongivore Vermivore reproductive Oophagy Paedophagy Placentophagy Breastfeeding Weaning cannibalistic Animal cannibalism Human cannibalism Self-cannibalism Sexual cannibalism
Herbivores	Folivore Frugivore Graminivore Granivore Nectarivore Palynivore Xylophagy Osteophagy
Cellular	Phagocytosis Myzocytosis
Others	Bacterivore Fungivore Coprophagia Detritivore Geophagia Omnivore Planktivore Saprophagy Xenophagy
Methods	Ambush predator Apex predator Bait balls Bottom feeding Browsing Feeding frenzy Filter feeding Grazing Hypercarnivore Hypocarnivore Intraguild predation Kleptoparasitism Lunge feeding Mesocarnivore Pivot feeding Ram feeding Scavenging Suction feeding Trophallaxis
Predation Antipredator adaptation Carnivorous plant Carnivorous fungus Carnivorous protist Category:Eating behaviors

Fish
About fish	Diversity Ethnoichthyology Evolution Diseases and parasites Fisheries Fishing Fish as food Fear of fish FishBase Fish kill Hypoxia in fish Ichthyology
Anatomy and physiology	Fish anatomy Fish physiology Estimating age Anguilliformity Bone dermal intramembranous ossification Cleithrum Chromatophore Fins dorsal fin Gill branchial arch gill raker gill slit pharyngeal arch pharyngeal slit pseudobranch Glossohyal Jaw hyomandibula pharyngeal jaw Leydig's organ Mauthner cell Meristics Operculum papillare Papilla Photophore Root effect Shark cartilage Scales ganoine Spiral valve Suckermouth Swim bladder physoclisti physostome Teeth pharyngeal teeth shark teeth Teleost leptins Digital Library
Sensory systems	Sensory systems in fish Ampullae of Lorenzini Barbel Hydrodynamic reception Electrocommunication Electroreception Jamming avoidance response Lateral line Otolith Passive electrolocation Capacity for pain Schreckstoff Surface wave detection Vision Weberian apparatus
Reproduction	Fish reproduction Bubble nest Clasper Egg case Fish development Ichthyoplankton Juvenile fish Life history theory Milt Mouthbrooder Polyandry in fish Pregnancy Roe Sequential hermaphroditism Spawning triggers
Locomotion	Fish locomotion Fin and flipper locomotion Amphibious fish Walking fish Flying fish Undulatory locomotion Tradeoffs for locomotion in air and water RoboTuna
Other behaviour	Aquatic predation Aquatic respiration Bait ball Bottom feeders Cleaner fish Diel vertical migration Electric fish Filter feeders Forage fish Migrating fish Paedophagy Predatory fish Salmon run Sardine run Scale eaters Schooling fish Sleep in fish Venomous fish Fish intelligence
By habitat	Cave Coastal Coldwater Coral reef Deep sea Demersal Euryhaline Freshwater Groundfish Pelagic Tropical
Other types	Bait Coarse Diversity Game Genetically modified Hallucinogenic Oily Poisonous Rough Whitefish
Commercial	Fish farming Carp Salmonids Tilapia Wild fisheries Predatory fish billfish mackerel salmon tuna Forage fish anchovy herring sardine sprats Demersal fish cod flatfish pollock
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