Freshwater Aquarist

Popular Fish Species for your Aquarium

Here are some of the most popular freshwater fish species that are commonly kept in aquariums, each with unique characteristics and care requirements.

A common rule of thumb for how many freshwater fish you can keep in an aquarium is to allow about 1 inch of fish per gallon of water; however, this can vary depending on the specific fish species, their adult size, activity level, and bioload, with heavily planted or densely stocked tanks often needing more filtration and swimming room.

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Bristlenose Pleco

Bristlenose Pleco

Overview The Bristlenose Pleco (Ancistrus cf. cirrhosus) is the familiar bristlenose catfish sold in most stores. Males grow fleshy bristles on the snout. Grows to about 5 in (12.5 cm) standard length, much smaller than the common pleco. Mass-bred commercially. Its...

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Common Pleco

Common Pleco

Overview "Common Pleco" is a trade name for several large suckermouth catfish, most often the Amazon sailfin catfish (Pterygoplichthys pardalis). Store fish may be a related species or Hypostomus plecostomus. P. pardalis is native to the Amazon basin in Brazil and...

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Otocinclus Catfish

Otocinclus Catfish

Overview "Otocinclus" or "oto" covers several small algae-eating catfish. The one sold most often is probably Otocinclus macrospilus. Shipments are often mixed species. O. macrospilus comes from the upper Amazon in Peru, and possibly Colombia and Ecuador. Grows to...

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Zebra Danio

Zebra Danio

Overview The Zebra Danio (Danio rerio) is a hardy, blue-and-gold striped cyprinid, also known as the zebrafish. Native to the Ganges basin and nearby areas of northern India and surrounding countries. Grows to about 2 in (5 cm) standard length. Long-finned and other...

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Scarlet Badis

Scarlet Badis

Overview The Scarlet Badis (Dario dario) is one of the smallest percoid fish. Males are bright red with blue bars. Found in tributaries of the Brahmaputra in West Bengal and Assam, India. Grows to about 0.8 in (2 cm) standard length. A popular nano fish. Feeding A...

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Sailfin Pleco

Sailfin Pleco

Overview The Sailfin Pleco (Pterygoplichthys gibbiceps) is a large suckermouth catfish with a tall dorsal fin and a leopard-like pattern. Native to the Amazon and Orinoco basins in Brazil, Ecuador, Peru and Venezuela. Can reach around 18–20 in (45–50 cm). Feeding An...

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