Keeping small freshwater aquarium fish is a peaceful and creative hobby. I have been keeping a variety of small freshwater fish in my aquarium for a long time. For me, it is not only a hobby but also a way to raise awareness about animals and the environment. By observing different species of fish and their unique behavior, I can gain knowledge about their life cycle and ecosystem.
I keep many types of freshwater fish in my aquarium. In this fish-keeping vision of mine, I am discussing fish that are easy to keep, enhance the beauty of the aquarium, and are easily available, so that beginners can easily learn to choose fish for their aquarium.
1. Harlequin Rasbora
Harlequin-rasbora
Species Overview
- Scientific Name: Trigonostigma heteromorpha
- Common Name: Harlequin Rasbora
- Family: Cyprinidae
- Water Type: Freshwater fish
- Size: Mature Harlequin Rasboras are usually up to 4.5 cm (about 1.7 inches) long.
- Behavior: Harlequin Rasboras are a calm and social species. They generally like to be in groups.
- Color: The body surface of the Harlequin Rasbora is bright orange-red or pink in color.
- Origin: They are found in forested swamps and freshwater rivers in Southeast Asia, especially Thailand, Malaysia, and Singapore.
- Lifespan: 5–6 years
Harlequin Rasbora Care
Water Conditions and Parameters: They need a tank of at least 20 gallons (75 liters) in size to keep them. A temperature of 22°–26°C (72°–79°F), a pH level of 6.0 to 7.5, and a water hardness of 2 to 15 degrees dGH are best for them. At least 25–30% of the water should be changed every week.
Diet: They are omnivorous but prefer flake food or pellets, small insects or larvae, brine shrimp, daphnia, and bloodworms, etc. A variety of foods should be provided for a balanced diet.
Breeding
They lay eggs, usually under leaves. Eggs take 24–36 hours to hatch. Micro-foods are given for the first few days after the fry is born.
Partner Selection
Suitable Companions: They are peaceful fish. Other peaceful fish should be selected along with them to maintain a healthy and safe environment in the aquarium. Suitable companions include neon tetras, guppies, cherry barbs, etc.
Unsuitable Companions: Fish or animals that may chase or attack Rasboras should not be kept together, e.g., cichlids, angelfish, redtail sharks, gars, oscar fish, and betta fish.
Suitable Plants
Plants that Harlequin Rasboras like to shelter in and under, such as Java fern, Anubias, and Amazon sword, can be kept in the aquarium.
2. Blood Characin
Blood-characin
Species Overview
- Scientific Name: Aphyocharax anisitsi
- Common Name: Blood Characin
- Family: Characidae
- Water Type: Freshwater fish
- Size: Blood Characin grows to an average size of about 5-6 cm.
- Behavior: Blood Characin is quite calm and loves to be in groups. However, in some cases, it can become aggressive, especially towards smaller fish.
- Coloration: Their bodies are usually silvery, but their fins are bright red or crimson, giving them the name “Blood”.
- Origin: Rivers and lakes of South America
- Lifespan: With proper care and diet, the average lifespan of a Blood Characin can be up to 5-8 years.
Blood Characin Care
Water Conditions and Parameters: A tank of at least 20 gallons is required for keeping Blood Characins. As they like to swim in groups, numbers of 6 or more should be kept. Their water temperature should be between 22-28 °C (72°–82°F), with a pH level of 6.0-7.5, and GH (General Hardness) between 2-15 dGH. A 25%-50% water change every week is necessary to maintain a clean and healthy environment in the tank.
Diet: Blood Characins are omnivorous, meaning they eat both animal and plant-based foods. Their diet may include flakes, pellets, small worms, daphnia, and brine shrimp.
Breeding
Blood Characin breeding is relatively easy. The female fish lays the eggs, and the male fertilizes them. Eggs take about 24-48 hours to hatch. Infusoria or newly hatched brine shrimp are used as food for the fry.
Partner Selection
Suitable Mates: Choosing suitable mates for Blood Characins is very important, as they are generally calm in nature but can be aggressive towards smaller fish in some cases. Suitable companions include Tetra species, Harlequin Rasbora, Chili Rasbora, shrimp, etc.
Unsuitable Mates: Invasive species of fish are not suitable for Blood Characins. For example: Betta Fish, Angelfish, Guppy, Goldfish, etc.
Appropriate Plants
It is very important to have appropriate plants in the tank for Blood Characins, as the plants mimic the fish’s natural environment and provide them with hiding and resting areas. Suitable plants include Anubias, Java Fern, Java Moss, Amazon Sword, etc.
3. Panda Catfish
Panda-catfish
Species Overview
- Scientific name: Corydoras panda
- Common names: Panda Corydoras, Panda Cory
- Family: Corydoras
- Water type: Freshwater fish
- Size: Adult panda catfish are up to about 5 cm (2 in) in size.
- Behavior: Panda catfish love to move in groups. They are very calm in nature, get along easily with other fish, and spend a lot of time at the bottom of the aquarium.
- Coloration: Their bodies are white or light pink, with black patches near the fins and around the eyes.
- Origin: Their native habitat is the swampy areas of Peru, South America.
- Lifespan: They can live up to about 10 years with proper care and water quality.
Panda Catfish Care
Water conditions and parameters: At least a 20-25 gallon tank is needed to keep panda catfish. Water temperature should be kept at 22-26 °C (72-78°F), with a water pH of 6.0-7.5 and water hardness of 2-12 dGH. 20-30% of the water should be changed every week to maintain good water quality.
Diet: Panda catfish are omnivorous fish; they like to eat a variety of foods. They are given sinking pellets, wafers, bloodworms, brine shrimp, and cut-up vegetables (boiled cucumbers, pumpkins) to maintain their health and development.
Breeding
Female panda catfish usually lay eggs on plants, substrates, or tank walls. The eggs typically hatch after 3-5 days. After hatching, they begin to swim freely within a few days.
Partner Selection
Suitable Mates: Panda catfish are generally calm and social fish, so when choosing their mate, they should be paired with calm and social fish. For example, Neon Tetra, Guppy, Otocinclus, and Zebra Danio are suitable companions.
Unsuitable Companions: There are some fish that are not safe for panda catfish, such as Red-tailed Sharks, Bala Sharks, African Cichlids, Large Barbs, and Goldfish. These fish are very aggressive and can be dangerous for them.
Suitable Plants
There are a few things to keep in mind when choosing suitable plants for panda catfish, such as soft foliage, safety, and compatibility with the tank environment. Considering all these aspects, suitable plants for them are Java Fern, Anubias, Marimo Moss Ball, and Hornwort.
4. Glowlight Tetra
Glowlight-tetra
Species Overview
- Scientific Name: Hemigrammus erythrozonus
- Common Name: Glowlight Tetra
- Family: Characidae
- Water Type: Freshwater
- Size: Adult Glowlight Tetras are typically 2.5 cm to 4 cm (1-1.5 in) long.
- Behavior: The Glowlight Tetra’s temperament is very calm and social. They generally like to live in groups and can easily get along with other calm fish.
- Color: Their main color is transparent or bright yellow with a bright white stripe on the body. They have a slight sheen on the surface and belly.
- Origin: Mainly found in the rivers of South America, especially in the regions of Brazil and Paraguay.
- Lifespan: Generally, they can live 2 to 5 years under good care. However, proper care, quality food, and a healthy aquarium environment can help extend the lifespan of these fish.
Glowlight Tetra Care
Aquatic Conditions and Parameters: If you plan to keep multiple fish or other species, a 75-liter (20-gallon) or larger tank is best. Water Temperature 20-26 °C (68-79 °F), pH: 6.0-7.5, and Water Hardness: 4-20 d. Need to keep gay. 10-20% of the water should be changed every week to keep the water clean.
Diet: Glowlight Tetras are generally both carnivores and herbivores, so a variety of food should be provided for them. They can eat almost all types of flake food, granules, and zinger food.
Breeding
Breeding usually occurs in the morning. The male fish follows the female fish, and they move to a specific location where the female fish lays eggs. A female can usually lay 100-200 eggs. The eggs will begin to hatch in about 24-36 hours. After the eggs hatch, the young fish usually start swimming within five days.
Partner Selection
Suitable Mate: Choosing a suitable mate is important for Glowlight Tetras, as they are calm and social fish. Fish like Neon Tetra, Corydoras Catfish, Rasbora, etc., can be suitable companions for them.
Unsuitable Companions: Large or aggressive fish, such as cichlids or some large gar, should be avoided, as they can be dangerous to the Glowlight Tetra.
Suitable Plants
Suitable plants for Glowlight Tetras are Java Fern, Anubias, Cryptocoryne, Amazon Sword, Water Sprite, etc., which provide excellent shelter for fish and enhance the beauty of the aquarium.
5. Pea Puffer
Pea-puffer
Species Overview
- Scientific name: Carinotetraodon travancoricus
- Common Name: Pea Pufferfish or Dwarf Pufferfish
- Family: Tetraodontidae
- Water type: Freshwater pufferfish
- Size: Usually 1-2 inches (2.5-5 cm) long
- Behavior: They are very curious and somewhat aggressive, especially when defending their territory
- Color: Greenish or brown body with black spots and dots
- Origin: Mainly found in certain areas of India and Sri Lanka
- Lifespan: Generally ranges from 3 to 5 years
Pea Puffer Care
Water Conditions and Parameters: A single Pea Puffer needs at least a 5-gallon tank. However, if multiple puffers are kept, an additional 3-5 gallons will be required for each puffer.
Water temperature should be kept at 25-28°C, with a pH of 7.0 to 8.0, water hardness of 5 to 15 dGH, and ammonia and nitrite levels at 0 ppm.
20-25% of the water should be changed weekly to keep the tank clean and healthy.
Diet: Pea Puffers are primarily predatory fish, and their diet consists of live food (bloodworms, daphnia, mosquito larvae), dry food (flakes or pellets), and snails to help maintain their teeth.
Breeding
Pea Puffers usually breed during the summer season. Females can lay 20-30 eggs, typically on plants or in a safe place. The male stays next to the female and fertilizes the eggs during spawning. Eggs usually hatch in 3-5 days.
Partner Selection
Suitable Mates: The Pea Puffer is an aggressive fish, so choosing their tank mates is very important. Cherry Barb, Cardinal Tetra, and Harlequin Rasbora are suitable companions.
Unsuitable Companions: Pea Puffers are small and very aggressive, so they can be harmed when kept with larger fish. They are often best kept alone.
Suitable Plants
Choosing the right plants is important for the Pea Puffer’s health, as they enjoy hiding places and slow-moving water. Suitable plants include Java Moss, Anubias, Hornwort, Java Fern, and Cryptocoryne.
6. Tiger Barb
Tiger-barb
Species Overview
- Scientific Name: Puntigrus tetrazona
- Common Name: Tiger Barb
- Family: Cyprinidae
- Water Type: Freshwater
- Size: Usually 2.5 to 3 inches (about 6 to 7.5 centimeters) long as adults.
- Behavior: Tiger Barbs are very active and can sometimes become aggressive, especially if the aquarium does not have enough space and companionship.
- Color: Their bodies usually have an orange-red or golden hue, combined with black vertical stripes to create a “tiger” look.
- Origin: Rivers and water bodies of Southeast Asia.
- Lifespan: Tiger Barb fish generally have a lifespan of 5 to 7 years.
Care of Tiger Barb
Water Conditions and Parameters: Tiger Barbs require a tank with a capacity of 20 gallons or more. A water temperature of 75°F to 82°F (24°C to 28°C), a water pH of 6.0 to 7.5, and a water hardness of 4 to 10 dGH are required.
25-30% of the water should be changed every week to maintain good water quality in the tank.
Diet: Tiger Barbs are omnivorous fish, which means they like to eat a variety of foods. Their diet should include flake food, frozen food, live food (e.g., earthworms, artemia), and vegetables (e.g., boiled peas).
Breeding
The female fish lays about 200 to 300 eggs, which are immediately fertilized by the male fish and hatch into fry within 24 to 36 hours. After spawning, the eggs may be eaten, so the parents should be moved to a separate tank when breeding is complete.
Partner Selection
Suitable Mates: Tiger Barbs can be somewhat aggressive, so they should be kept with fish that can adapt to their mobility and behavior. For example, other varieties of barbs, as well as fish like danios, plecos, or loaches, can adapt well to them.
Unsuitable Mates: Certain species of fish are not suitable for Tiger Barbs due to their aggressive behavior, particularly their tendency to bite fins. Some unsuitable fish include Betta Fish, Angelfish, Guppies, and Goldfish.
Suitable Plants
Tiger Barbs are very active fish, so they need to have some hiding places in the vegetation. Suitable plants for them can be Anubias, Amazon Sword, Java Moss, and Java Fern.
7. Otocinclus
Otocinclus
Species Overview
- Scientific Name: Otocinclus affinis
- Common Name: Otocinclus catfish or Otos
- Family: Loricariidae
- Water Type: Freshwater
- Size: Can grow up to 1.5 to 2 inches (3.8 to 5 cm).
- Behavior: Peaceful and gregarious
- Color: The basic color is grey, light brown, or greenish. The areas on the chest and abdomen are usually light or white. They have black or dark brown stripes or spots on the sides of their bodies, which extend the entire length of their bodies. Their eyes are usually black or brown in color.
- Origin: South American freshwater rivers and lakes
- Lifespan: Generally 3 to 5 years
Care of Otocinclus
Water Conditions and Parameters: Although Otocinclus are small fish, tanks of 20 gallons or larger are ideal for them. The water temperature should be 22°-26°C (72°-79°F), with a pH of 6.8 to 7.5, and water hardness should be soft to moderate (dGH 5-15).
Diet: They feed on algae and organic waste, but if your tank doesn’t have enough algae, they can be fed specially formulated algae tablets or vegetables (such as zucchini or cucumber).
Breeding
The female Otocinclus usually lays eggs on algae or smooth surfaces at the bottom of the tank. They can lay 20-30 eggs at a time. The fish eggs usually hatch after 3-5 days. The hatching larvae first feed on algae and small organic matter.
Partner Selection
Suitable Companions: Otocinclus fish can easily mix with other peaceful fish like tetras, guppies, and platys.
Unsuitable Mates: Otocinclus are very small and peaceful, so aggressive and larger fish like angelfish, bettas, Arowanas, and crayfish can chase or hurt them.
Suitable Plants
Choosing the right plants in an aquarium for Otocinclus fish is important because plants act as food (algae) and shelter for Otocinclus. Plants also help maintain water quality. Suitable plants for these include Java Moss, Java Fern, Anubias, and Hornwort.
8. Cherry Barb
Cherry-barb
Species Overview
- Scientific Name: Puntius titteya
- Common Name: Cherry Barb
- Family: Cyprinidae
- Water Type: Freshwater
- Size: Usually 2 to 3 inches (5-8 cm) long.
- Behavior: The Cherry Barb is generally calm and social. They usually get along with other calm fish.
- Color: The color of Cherry Barbs is usually bright red or pink, especially in male fish. Females are slightly less brightly colored and are generally fuller.
- Origin: Asia Minor
- Lifespan: Cherry Barbs have a normal lifespan of 3 to 5 years, but with proper care and a healthy environment, they can live for more than 5 years.
Care of Cherry Barb
Water Conditions and Parameters: The minimum tank size is 20 gallons. Water temperature should be between 22 to 26 °C (71 to 78°F). A pH of 6.0 to 7.5 and a water hardness of 5 to 15 dGH are suitable for them.
Diet: The Cherry Barb is omnivorous. They prefer to eat flake food, pellets, small worms or insects (such as tubifex worms), and live food (such as daphnia). Green plants and vegetables (such as spinach or zucchini) should be included in their diet for proper nutrition.
Breeding
Cherry Barbs usually lay their eggs on the underside of leaves. It is better to create a separate tank for them if you want to breed them. Females typically lay 30 to 55 eggs, and fry hatch within 2-3 days after fertilization.
Partner Selection
Suitable Mate: Choosing the right mate is very important for Cherry Barb fish, as it affects their natural behavior and health. Cherry Barbs are generally calm and social fish, so they should be kept with other calm fish. Suitable companions include German Blue Ram, Platy, and Tetra.
Unsuitable Companions: Some fish are not safe to mix with Cherry Barb fish, such as Cichlids, Snakehead Fish, and Leopard Ctenopoma, as they are aggressive and can cause stress.
Suitable Plants
Plants provide them with hiding places, which help relieve stress and provide security during breeding, so suitable plants are important. Suitable plants for them include Uba, Horton, Java Moss, Java Fern, and Speedyta.
9. Knight Goby
Knight-Goby
Species Overview
- Scientific name: Stigmatogobius sadanundio
- Common name: Knight Goby
- Family: Gobiidae
- Water type: Freshwater
- Size: Usually 3-4 inches (8-10 cm).
- Behavior: The Knight Goby is generally a calm and tolerant fish. Although they usually prefer to live alone, in the right environment, they can coexist with other peaceful fish.
- Color: Light to dark brown or grey. The body has small dots, which help them to hide underwater.
- Origin: Various regions of Southeast Asia
- Lifespan: Usually lives up to 3-5 years
Care of the Knight Goby
Water conditions and parameters: Generally, a minimum 15-20 gallon tank is required. Add 3-4 gallons of water for each new fish. Water temperature should be 24°C to 28°C (75°F to 82°F), pH level 6.5 to 7.5, and water hardness 8-12 dGH. Twenty to twenty-five percent of the water should be changed every week to maintain the health of the water.
Diet: Choosing the right diet for the Knight Goby is very important for their health. They like to eat live food (Artemia, Daphnia), pellets, and vegetables.
Breeding
Female fish usually lay 30 to 60 eggs. The eggs are usually under the sand and are safe. The male fish takes proper care of the eggs and protects them. Hatchlings usually hatch in 2-3 days.
Partner Selection
Suitable mates: It is very important to select suitable mates for the Knight Goby so that they can live in a healthy and safe environment. Some suitable companions for the Knight Goby are Tiger Goby, Neon Tetra, or Cardinal Tetra.
Unsuitable mates: Unsuitable mates for the Knight Goby include Oscar or African Cichlids, Rainbowfish, and Betta Fish, as they are aggressive and predatory.
Suitable Plants
Choosing the right plants for the Knight Goby is important for their health. Plants serve as their shelter, hiding place, and food source. Suitable plants for them can be Java Moss, Anubias, Woodpeas, and Perennial Grass.
10. White Cloud Mountain Minnow
White-Cloud-Mountain-Minnow
Species Overview
- Scientific name: Tanichthys albonubes
- Common name: White Cloud Minnow or White Cloud Mountain Fish
- Family: Cyprinidae
- Water type: Freshwater
- Size: Usually 1.5 to 2 inches (4 to 5 cm) long.
- Behavior: These fish are generally calm in nature and like to be together, so it is better to keep them with other calm fish.
- Color: The body of the fish is thin and white to pale yellow in color. Male fish are usually more colorful, with bright red or orange spots on their dorsal fins, while female fish are usually rounder and more robust, appearing egg-shaped.
- Origin: China
- Lifespan: Usually 3 to 5 years.
Caring for the White Cloud Mountain Minnow
Aquatic Conditions and Parameters: Since these fish are social and gregarious, a 20-25 gallon tank is needed to keep 5-6 fish.
Water temperature needs to be maintained at 18-24°C (64-75°F), with a pH level of 6.5-7.5 and water hardness of 5-19 dGH.
Ensure regular water changes (10-15% weekly) and filtering to keep the water clean and healthy.
Diet: The diet of the White Cloud Mountain Minnow is quite diverse, and they eat different types of food such as flake food, granular food, live food, frozen food, etc.
Breeding
Breeding the White Cloud Mountain Minnow is an interesting process and can usually be done easily in an aquarium. The female fish will typically lay 100-200 eggs on the leaves of the plants, and then the fish should be separated from the breeding tank to avoid eating the eggs. The eggs hatch after 3-7 days. After hatching, they should be given small and nutritious food such as infusoria or special flake food.
Mate Selection
Suitable Mates: Choosing suitable mates is very important for the White Cloud Mountain Minnow, as it is conducive to their health and helps maintain a social environment. Guppy fish, other minnow species, tetras, etc., can be suitable companions for them.
Unsuitable Companions: Some companions are not suitable for the White Cloud Mountain Minnow and should not be kept with them, such as cichlids, tiger barbs, piranhas, and crayfish, as they are aggressive and very active, which may lead to chasing and attacking the White Cloud Mountain Minnow.
Suitable Plants
Choosing the right plants for the White Cloud Mountain Minnow is critical to their survival. The right plants provide shelter, and security, and improve the water environment. Suitable plants for them include Java fern, Anubias, Cryptocoryne, Hornwort, etc.
