Freshwater Fish Profiles

Explore our growing database of freshwater fish species. Each profile includes detailed care requirements, compatibility data, and environmental needs to help you build the perfect aquarium.

Showing 577 - 600 of 736 Fish Profiles

Reticulated Stingray (Teacup Ray)

Potamotrygon orbignyi

Oddballs

65 cm Mostly Peaceful

The Reticulated Stingray is a stunning bottom-dwelling freshwater ray native to South America. It is commonly sold under the deceptive trade name 'Teacup Ray' as a juvenile. They grow massive, have a venomous tail spine, and demand pristine water quality, massive aquariums, and a strict carnivorous diet. A fine sand substrate is an absolute requirement to prevent fatal bacterial infections from underside abrasions.

Rhomb Barb

Desmopuntius rhomboocellatus

Cyprinids

5.5 cm Peaceful

A striking, peaceful schooling fish from the peat swamps of Borneo. Known for the distinctive snake-skin or rhomboid markings on its flanks. Unlike the related Tiger Barb, it is completely peaceful and somewhat shy, requiring heavily planted tanks with tannin-stained (blackwater) conditions to feel secure and show its best reddish-orange colors.

Riffle Shrimp

Australatya striolata

Invertebrates

6 cm Peaceful

A fascinating freshwater filter-feeding shrimp native to the fast-flowing creeks (riffles) of Eastern Australia. They possess specialized fan-like appendages used to catch suspended microscopic food from the water column. They require highly oxygenated water with strong flow and are sensitive to poor water quality. They are completely peaceful but known to be excellent climbers and jumpers.

Rio Negro Dwarf Cichlid

Ivanacara adoketa

Cichlids - South American

10 cm Aggressive

A stunning but highly aggressive blackwater cichlid from the Rio Negro basin in Brazil. Famous for its striking 'zebra' striping, especially during courtship. They require very soft, highly acidic water to thrive. Despite being categorized sometimes as 'dwarf' cichlids, they possess the temperament of much larger Central American species and are best kept in species-only setups or pairs.

Rose Danio

Danio roseus

Cyprinids

4 cm Peaceful

A lively and colorful schooling fish from Southeast Asia. Rose Danios are characterized by their pinkish-purple iridescence, which becomes especially vibrant in well-planted tanks with subdued lighting. Like all Danios, they are incredibly active swimmers and prolific jumpers, requiring a tight-fitting lid and a horizontally long tank to accommodate their energetic nature.

Rosy Barb

Pethia conchonius

Cyprinids

10 cm Mostly Peaceful

A hardy, active, and colorful subtropical schooling fish. Known for the male's striking rosy-red breeding dress, while females are more golden/silver. They are voracious eaters, very active swimmers, and can be fin-nippers if kept in too small a group. Best kept in cooler water compared to tropical species. The Long Finned morph is also popular but requires gentler flow.

Rosy Finned Tetra

Hyphessobrycon rosaceus

Characins

4 cm Peaceful

A beautiful, deep-bodied tetra known for its reddish-pink hue and striking dorsal fin, which features a prominent black patch and white tip. They are peaceful, active schooling fish that thrive in heavily planted tanks with slightly acidic, soft water. Males frequently engage in harmless mock-battles by flaring their fins to establish hierarchy.

Rosy Red Minnow / Fathead Minnow

Pimephales promelas

Cyprinids

7.5 cm Peaceful

A highly adaptable, temperate-water schooling fish native to North America. Most commonly encountered in the aquarium trade as the brightly colored 'Rosy Red' morph (often sold as a feeder fish). They are incredibly hardy, active, and peaceful, making excellent dither fish for unheated aquariums, goldfish tanks, or indoor ponds.

Royal Farlowella Catfish

Sturisoma panamense

Catfish

25 cm Peaceful

A striking, elongated catfish known for its twig-like appearance, prominent dorsal fin, and long tail filaments. They are excellent grazers that spend their time clinging to driftwood, broad-leaved plants, and aquarium glass. Highly peaceful but sensitive to poor water quality and starvation. A constant supply of biofilm, algae, and driftwood is essential.

Royal Pleco (L190)

Panaque nigrolineatus

Catfish

43 cm Semi-Aggressive

A stunning, large-growing pleco famous for its red eyes, grey/green coloration, and dark horizontal stripes. Belonging to the genus Panaque, they are xylophagous (obligate wood-eaters); real driftwood in the aquarium is absolutely essential for their digestion and survival. They produce extreme amounts of sawdust-like waste and require heavy, high-flow filtration.

Ruby Green Hap

Haplochromis sp. 'Ruby Green'

Cichlids - African

11 cm Aggressive

A stunning, highly endangered cichlid from the Lake Victoria basin (specifically Lake Nawampasa). They are renowned for their intense split coloration. Like most Victorian cichlids, they are maternal mouthbrooders with high levels of conspecific aggression, requiring a rocky, hard-water setup with a strict harem ratio.

Rummy-Nose Tetra

Hemigrammus rhodostomus

Characins

5 cm Peaceful

Renowned as the tightest schooling fish in the freshwater hobby. They feature a bright red nose, a silver body, and a black-and-white checkered tail. They are excellent 'indicator fish'; their red noses will fade to pale pink if water quality drops or the fish are stressed. While there are three very similar species (H. rhodostomus, H. bleheri, P. georgiae) often sold under the same name, their care requirements are identical.

Rummynose Rasbora

Sawbwa resplendens

Cyprinids

3.5 cm Peaceful

An active, striking nano fish endemic to Inle Lake in Myanmar. Uniquely, they are completely scaleless. They strictly require hard, alkaline water to thrive and are sensitive to medications due to their lack of scales. They are schooling fish that must be kept in groups to feel secure and display their best behavior.

Rusty Cichlid

Iodotropheus sprengerae

Cichlids - African

10.5 cm Semi-Aggressive

An endemic Mbuna from Lake Malawi, known for its unique rusty-orange to lavender coloration. It is widely considered one of the most 'peaceful' Mbuna species, making it an excellent choice for beginner African Cichlid keepers. However, like all Mbuna, they are territorial, require hard alkaline water, and need an aquarium with extensive rockwork to form caves and territories.

Saddled Bichir

Polypterus endlicheri

Oddballs

60 cm Semi-Aggressive

A massive, prehistoric-looking predatory fish native to Africa. Known for its prominent dorsal finlets, striking 'saddled' striping, and ability to breathe atmospheric air using a modified swim bladder. They are bottom-dwelling ambush predators. They are completely peaceful to fish too large to swallow, but highly predatory toward anything else. They must be kept on soft sand, as they swallow their prey whole and ingested gravel can be fatal.

Sailfin Molly

Poecilia latipinna

Livebearers

10 cm Mostly Peaceful

A large, highly active livebearer famous for the male's spectacular, sail-like dorsal fin. They are strictly hard-water fish and are prone to the 'shimmies' or secondary infections in soft, acidic water. They are excellent algae grazers and prolific breeders. Males relentlessly pursue females, so a minimum ratio of 1 male to 2 females is required to prevent exhaustion.

Sajica Cichlid (T-Bar Cichlid)

Amatitlania sajica

Cichlids - Central American

12 cm Semi-Aggressive

A relatively manageable Central American cichlid closely related to the Convict Cichlid. It earns its 'T-Bar' name from a prominent dark vertical bar crossed with a horizontal stripe on its flank. While more peaceful than many CA cichlids, they are dedicated parents and become fiercely territorial when breeding, often excavating large pits in the substrate. They thrive in moderately hard water.

Salvini Cichlid

Trichromis salvini

Cichlids - Central American

22 cm Highly Aggressive

The Salvini Cichlid is a stunning but notoriously aggressive Central American cichlid. In a rare twist for cichlids, females are actually more brightly colored than males, displaying vivid yellow bodies with striking red bellies and contrasting black markings. They are highly territorial ambush predators and will actively hunt smaller fish. Best kept in a large, species-only setup or with similarly robust, heavily armored tank mates.

San Juan Cory

Corydoras bilineatus

Catfish

4.5 cm Peaceful

The San Juan Cory (recently reclassified as Gastrodermus bilineatus) is a small, attractive, and peaceful armored catfish native to the Madeira River basin in Bolivia. It features a striking pattern of white stripes along a dark body. Like all Corydoras, they are obligate air-breathers and social bottom-dwellers that must be kept in schools. They require a soft sand substrate to protect their delicate sensory barbels.

Saulosi Cichlid

Chindongo saulosi

Cichlids - African

8.5 cm Aggressive

A critically endangered 'dwarf' Mbuna cichlid from Lake Malawi, famous for its extreme sexual dimorphism. Females and juveniles are a vibrant, solid yellow, while dominant males transform into a striking light blue with thick black vertical bars. Like all Mbuna, they are rock-dwelling aufwuchs grazers that require a strict harem structure (1 male to 3+ females) to manage their aggressive and territorial nature.

Scarlet Badis

Dario dario

Other

2 cm Mostly Peaceful

One of the smallest known aquarium fish, resembling a tiny jewel. Males display brilliant vertical red and iridescent blue stripes. While beautiful, they are known for being extremely picky eaters, often refusing dry foods and requiring live or frozen micro-foods (Daphnia, Baby Brine Shrimp). Males act like tiny Cichlids and will stake out territories.

Scat (Brackish)

Scatophagus argus

Oddballs

30 cm Mostly Peaceful

A highly active, large schooling fish found in Indo-Pacific estuaries. 'Scatophagus' translates to 'dung-eater', pointing to their voracious, omnivorous appetite and the massive amount of waste they produce. While juveniles can tolerate light brackish water, adults strictly require heavy brackish to full marine conditions. They possess mildly venomous dorsal spines.

Schwartz's Cory

Corydoras schwartzi

Catfish

6.5 cm Peaceful

A peaceful and active bottom-dwelling catfish native to the Purus River basin in Brazil. Identifiable by its striking pattern of black horizontal stripes and a tall dorsal fin. Like all Corydoras, they are highly social shoaling fish that must be kept in groups and require a soft sand substrate to protect their delicate sensory barbels.

Scissortail Rasbora

Rasbora trilineata

Cyprinids

13 cm Peaceful

A highly active, streamlined schooling fish named for its deeply forked tail with black and white bands. As they swim, the tail stripes create a scissor-like opening and closing motion. While very peaceful, they are fast, restless swimmers that require long aquariums to thrive and may outcompete slower or shy tank mates for food.