Fish Guide: 43 Tropical Fish, Medaka, Goldfish & Koi Care Notes

Tropical fish (24)Medaka, goldfish & koi (12)Shrimp (3)Large fish (4)

Care notes are the same as the in-game guide. For a real tank, adjust for tank size, tankmates and your local water. Images are the in-game 3D models.

Tropical fishTropical fish

Small to medium fish from South America, Southeast Asia and beyond, kept warm with a heater.

Neon Tetra

Paracheirodon innesi

Native to: South America (Amazon)

Difficulty ★★☆☆☆Size ~3 cmIdeal 23〜27℃Needs a heaterSchooling

Care notes

Feeding: Small pellets, once or twice a day.
Water: Prefers soft, slightly acidic water. Change water a little at a time.
Temperature: Keep at 24–26℃ with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: Struggles in a tank that is still cycling. Stunning in a school of 10 or more.

Guppy

Poecilia reticulata

Native to: South America (selectively bred)

Difficulty ★☆☆☆☆Size ~4 cmIdeal 22〜27℃Needs a heater

Care notes

Feeding: Once or twice a day. Keep it light — leftovers foul the water.
Water: Prefers slightly alkaline water. Hardy and beginner-friendly.
Temperature: About 24℃ with a heater.
Breeding: Livebearer — the female gives birth to fry. Keep males and females together and they breed on their own.
Common problems: They breed until the tank gets crowded.

Panda Cory

Corydoras panda

Native to: South America (Peru)

Difficulty ★★☆☆☆Size ~5 cmIdeal 22〜26℃Needs a heaterSchooling

Care notes

Feeding: Sinking tablets.
Water: Forages in the substrate, so use smooth, rounded sand.
Temperature: About 24℃ with a heater.
Breeding: Sometimes lays eggs on the glass.
Common problems: Sharp gravel damages their barbels.

Betta (Halfmoon)

Betta splendens

Native to: Thailand (selectively bred)

Difficulty ★★☆☆☆Size ~6 cmIdeal 25〜28℃Needs a heater

Care notes

Feeding: Betta pellets, 2–3 at a time, twice a day.
Water: Prefers a tank with gentle flow.
Temperature: About 26℃ with a heater.
Breeding: Males fight fiercely — keep only one male.
Common problems: Cold water and strong flow damage the fins.

Angelfish

Pterophyllum scalare

Native to: South America (Amazon)

Difficulty ★★★☆☆Size ~12 cmIdeal 24〜28℃Needs a heater

Care notes

Feeding: Twice a day. Adults may eat small fish.
Water: Give them a tall tank to glide around in.
Temperature: About 26℃ with a heater.
Breeding: Pairs lay eggs on driftwood or leaves.
Common problems: Will eat small fish like neon tetras.

Discus

Symphysodon spp.

Native to: South America (Amazon)

Difficulty ★★★★★Size ~14 cmIdeal 28〜30℃Needs a heater

Care notes

Feeding: Discus food, a little at a time, three times a day.
Water: Very sensitive to dirty water. Frequent water changes are a must.
Temperature: Warm: 28–30℃ with a heater.
Breeding: Parents feed their fry with mucus from their skin.
Common problems: Cold and dirty water. Known as the "King of the Aquarium" — for experienced keepers.

Rummy-nose Tetra

Hemigrammus rhodostomus

Native to: South America (Amazon)

Difficulty ★★☆☆☆Size ~4 cmIdeal 24〜28℃Needs a heaterSchooling

Care notes

Feeding: Small pellets, once or twice a day.
Water: The red head gets deeper in clean water. A pale head means the water is dirty.
Temperature: About 25℃ with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: Schools very tightly and turns in perfect unison. 10 or more recommended.

Red Mickey Mouse Platy

Xiphophorus maculatus

Native to: Central America (selectively bred)

Difficulty ★☆☆☆☆Size ~5 cmIdeal 21〜27℃Needs a heater

Care notes

Feeding: Eats anything, and nibbles algae too.
Water: Hardy, prefers slightly alkaline water. Great for beginners.
Temperature: About 24℃ with a heater.
Breeding: A livebearer like the guppy. The "Mickey Mouse" mark on the tail passes to the fry.
Common problems: Watch out — they multiply fast.

Otocinclus

Otocinclus spp.

Native to: South America

Difficulty ★★★☆☆Size ~4 cmIdeal 22〜27℃Needs a heater

Care notes

Feeding: Grazes algae on glass and plants. Give sinking tablets when algae runs low.
Water: Add only after the tank has cycled. Weak in brand-new tanks.
Temperature: About 24℃ with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: An adorable algae-eating pro that likes to cling to the glass.

Honey Gourami

Trichogaster chuna

Native to: India, Bangladesh

Difficulty ★★☆☆☆Size ~5 cmIdeal 24〜28℃Needs a heater

Care notes

Feeding: Small pellets twice a day. Happily eats from the surface.
Water: Prefers calm water.
Temperature: About 26℃ with a heater.
Breeding: Males build bubble nests at the surface.
Common problems: Feels its way around with thread-like fins. Gentle and peaceful.

Kuhli Loach

Pangio kuhlii

Native to: Southeast Asia

Difficulty ★★☆☆☆Size ~7 cmIdeal 24〜28℃Needs a heater

Care notes

Feeding: Leftovers on the bottom and sinking tablets.
Water: Likes fine sand. Gets active at night.
Temperature: About 25℃ with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: Wriggles along the bottom like a snake, and sometimes burrows into the sand.

Bristlenose Pleco

Ancistrus sp.

Native to: South America

Difficulty ★★☆☆☆Size ~10 cmIdeal 23〜28℃Needs a heater

Care notes

Feeding: Rasps algae and driftwood. Pleco wafers too.
Water: Loves driftwood. Messy, so use good filtration.
Temperature: About 25℃ with a heater.
Breeding: Males grow bushy "bristles" on their snouts.
Common problems: Rests by day and grazes the glass and wood at night. The best algae eater of all.

German Blue Ram

Mikrogeophagus ramirezi

Native to: South America (selectively bred)

Difficulty ★★★★☆Size ~5 cmIdeal 27〜30℃Needs a heater

Care notes

Feeding: Small pellets or frozen bloodworms, twice a day.
Water: Prefers clean, slightly acidic water. Sensitive to dirty water.
Temperature: Warm: about 28℃ with a heater.
Breeding: Pairs lay eggs on a stone and guard them.
Common problems: Colors fade in cold or dirty water. A small cichlid with jewel-like blue spots.

Albino Cory

Corydoras aeneus (albino)

Native to: South America (selectively bred)

Difficulty ★★★☆☆Size ~5 cmIdeal 22〜27℃Needs a heaterSchooling

Care notes

Feeding: Sinking tablets.
Water: Fine, rounded sand is best. A bit sensitive to dirty water.
Temperature: About 24℃ with a heater.
Breeding: An albino without pigment — red eyes and a pale pink body.
Common problems: Sharp gravel damages their barbels. In a group they scurry busily along the bottom.

Black Molly

Poecilia sphenops

Native to: Central America (selectively bred)

Difficulty ★☆☆☆☆Size ~6 cmIdeal 24〜28℃Needs a heater

Care notes

Feeding: Once or twice a day. Likes plant-based food and picks at algae on glass and plants.
Water: Prefers hard, slightly alkaline water. Change water often.
Temperature: About 25℃ with a heater. Doesn't like the cold.
Breeding: Livebearer — the female gives birth to fry. Keep males and females together to breed.
Common problems: Prone to ich in cold water.

Cardinal Tetra

Paracheirodon axelrodi

Native to: South America (Rio Negro)

Difficulty ★★☆☆☆Size ~4 cmIdeal 24〜29℃Needs a heaterSchooling

Care notes

Feeding: Small pellets, once or twice a day.
Water: Prefers soft, slightly acidic water. Colors pop in a tank with aqua soil.
Temperature: Around 26℃ with a heater — a little warmer than for Neon Tetras.
Breeding: Rarely breeds in a home aquarium.
Common problems: Looks like a Neon Tetra, but the red runs all the way to the chin. Breathtaking in a big school.

Celestial Pearl Danio

Danio margaritatus

Native to: Myanmar

Difficulty ★★☆☆☆Size ~3 cmIdeal 22〜26℃Needs a heaterSchooling

Care notes

Feeding: Very fine food twice a day. Their mouths are tiny.
Water: Prefers a calm, heavily planted tank.
Temperature: About 24℃ with a heater.
Breeding: Scatters eggs in dense plants, but the parents eat them.
Common problems: A tiny fish with fireworks-like spots, discovered in 2006. Shy, so give it plenty of plants.

Apistogramma agassizii

Apistogramma agassizii 'Double Red'

Native to: South America (Amazon, selectively bred)

Difficulty ★★★☆☆Size ~7 cmIdeal 25〜29℃Needs a heater

Care notes

Feeding: Small pellets or frozen bloodworms, twice a day.
Water: Likes soft, slightly acidic water and hiding spots among driftwood and leaves.
Temperature: 26–27℃ with a heater.
Breeding: A pair lays eggs in the shade of driftwood, and the female guards them.
Common problems: Males fight over territory, so one male is safest. A dwarf cichlid famous for its red-edged tail.

Clown Loach

Chromobotia macracanthus

Native to: Indonesia

Difficulty ★★☆☆☆Size ~15 cmIdeal 25〜29℃Needs a heaterSchooling

Care notes

Feeding: Sinking tablets once or twice a day. They also love eating pest snails.
Water: Keep with friends in a tank full of hiding spots.
Temperature: About 26℃ with a heater.
Breeding: Does not breed in a home aquarium.
Common problems: Grows slowly to about 15cm over the years. You may be startled to see one resting on its side.

Blue Diamond Discus

Symphysodon 'Blue Diamond'

Native to: Selectively bred

Difficulty ★★★★★Size ~14 cmIdeal 28〜30℃Needs a heater

Care notes

Feeding: Discus food, a little at a time, three times a day.
Water: Very sensitive to dirty water. Frequent water changes are a must.
Temperature: Warm: 28–30℃ with a heater.
Breeding: A carefully selected line that shines solid blue, with no stripes at all.
Common problems: One of the most beautiful of the "King of the Aquarium." Watch for cold and dirty water.

Platinum White Betta

Betta splendens 'Platinum White'

Native to: Thailand (selectively bred)

Difficulty ★★☆☆☆Size ~6 cmIdeal 25〜28℃Needs a heater

Care notes

Feeding: Betta pellets, 2–3 at a time, twice a day.
Water: Prefers a tank with gentle flow.
Temperature: About 26℃ with a heater.
Breeding: Pearly white fins appear only in carefully selected lines.
Common problems: Cold water and strong flow damage the fins.

Rasbora espei

Trigonostigma espei

Native to: Thailand, Cambodia

Difficulty ★☆☆☆☆Size ~3 cmIdeal 23〜28℃Needs a heaterSchooling

Care notes

Feeding: Small pellets, once or twice a day.
Water: Hardy and not fussy about water. Colors deepen in a well-planted tank.
Temperature: Keep at 24–26°C with a heater.
Breeding: Lays eggs under plant leaves, but rarely breeds in a home tank.
Common problems: Copper body with a black wedge. A school of 10+ looks stunning against green plants.

Boraras brigittae

Native to: Indonesia (Borneo)

Difficulty ★★☆☆☆Size ~2 cmIdeal 24〜28℃Needs a heaterSchooling

Care notes

Feeding: Its mouth is tiny, so give powder-fine food.
Water: Soft, slightly acidic water. Prefers a densely planted tank with gentle flow.
Temperature: About 25℃ with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: A bright red fish only about 2cm long. Larger fish will eat it.

Glowlight tetra

Hemigrammus erythrozonus

Native to: South America (Guyana)

Difficulty ★☆☆☆☆Size ~3 cmIdeal 23〜27℃Needs a heaterSchooling

Care notes

Feeding: Small pellets, once or twice a day.
Water: Hardy and easy. The red stripe glows best over dark substrate.
Temperature: Keep at 24–26°C with a heater.
Breeding: Rarely breeds in a home aquarium.
Common problems: A see-through body with one glowing red line. Mixes softly with neon tetras.

Medaka, goldfish & koiMedaka, goldfish & koi

Fish that live without a heater. In the game, koi live in the garden pond.

Yokihi Medaka

Oryzias latipes var.

Native to: Japan (selectively bred)

Difficulty ★☆☆☆☆Size ~4 cmIdeal 18〜28℃No heater neededSchooling

Care notes

Feeding: Once or twice a day, only what they finish in a few minutes. Loves floating food.
Water: Hardy and tolerant of changing water. Change about a third of the water once a week.
Temperature: Fine without a heater. Lays eggs above 20℃.
Breeding: Sticks eggs to plants. The parents eat them, so move the eggs to a separate container.
Common problems: Overfeeding fouls the water.

Ryukin Goldfish

Carassius auratus var.

Native to: Japan (selectively bred)

Difficulty ★☆☆☆☆Size ~9 cmIdeal 15〜27℃No heater needed

Care notes

Feeding: Goldfish food once or twice a day, as much as they eat in a few minutes. Big eaters, big mess.
Water: Very hardy, but messy — use strong filtration and change water often.
Temperature: No heater needed year-round. Slows down in winter.
Breeding: Spawns in spring as the water warms.
Common problems: Overstocking fouls the water. Will eat small shrimp.

White Cloud Minnow

Tanichthys albonubes

Native to: Southern China

Difficulty ★☆☆☆☆Size ~4 cmIdeal 16〜26℃No heater neededSchooling

Care notes

Feeding: Once or twice a day, as much as they eat in a few minutes. Eats anything.
Water: Very hardy and tolerant of changing water. A good companion while your first tank cycles.
Temperature: Survives winter without a heater (down to about 5℃).
Breeding: Scatters eggs among plants. Parents eat them, so dense plants help fry survive.
Common problems: Can jump out — keep a lid on.

Ranchu

Carassius auratus var.

Native to: Japan (selectively bred)

Difficulty ★★☆☆☆Size ~8 cmIdeal 15〜27℃No heater needed

Care notes

Feeding: Goldfish food once or twice a day. A clumsy swimmer, so sinking food is easier.
Water: Messy — use strong filtration and change water often. Keep flow gentle.
Temperature: No heater needed year-round.
Breeding: Known in Japan as the "King of Goldfish." No dorsal fin, and a prized fleshy head growth (wen).
Common problems: Strong flow wears them out. Will eat small shrimp and fry.

Miyuki Medaka (Full Body)

Oryzias latipes 'Miyuki'

Native to: Japan (selectively bred)

Difficulty ★☆☆☆☆Size ~4 cmIdeal 18〜28℃No heater neededSchooling

Care notes

Feeding: Once or twice a day, as much as they eat in a few minutes.
Water: Hardy. Change about a third of the water once a week.
Temperature: Fine without a heater.
Breeding: In the "Full Body" line the metallic shine covers the whole body — rare, and hard to pass on to offspring.
Common problems: The shine looks best from above.

Weather loach

Misgurnus anguillicaudatus

Native to: Japan

Difficulty ★☆☆☆☆Size ~8 cmIdeal 12〜28℃No heater needed

Care notes

Feeding: Eats leftovers on the bottom and sinking food.
Water: Tough and fine with a little dirt. A creature of rice paddies and streams.
Temperature: Survives winter without a heater — great for an outdoor lily bowl.
Breeding: Rarely breeds at home.
Common problems: Feels along the bottom with its whiskers. Before the weather changes, it may rise to gulp air.

Japanese rosy bitterling

Rhodeus ocellatus kurumeus

Native to: Japan

Difficulty ★★☆☆☆Size ~5 cmIdeal 12〜26℃No heater neededSchooling

Care notes

Feeding: Small pellets once or twice a day. It nibbles algae too.
Water: Likes clean water. Keep it in a calm, well-planted bowl or tank.
Temperature: Survives winter without a heater — great for an outdoor lily bowl.
Breeding: An unusual fish that lays its eggs inside freshwater mussels — no mussels, no breeding.
Common problems: In spring and summer, males flush an iridescent rosy purple. A Japanese native that’s becoming rare in the wild.

Comet (red & white)

Carassius auratus var.

Native to: USA (bred variety)

Difficulty ★☆☆☆☆Size ~10 cmIdeal 12〜28℃No heater needed

Care notes

Feeding: Goldfish food once or twice a day. A big eater — don’t overfeed.
Water: Hardy and fine with a little dirt. It grows large, so give it a roomy bowl or tank.
Temperature: Survives winter without a heater — a classic for outdoor bowls and ponds.
Breeding: Lays eggs on plants in spring, but rarely breeds at home.
Common problems: Glides along trailing a long streamer tail. It will eat small shrimp and baby medaka.

Golden weather loach

Misgurnus anguillicaudatus var.

Native to: Japan (color variety)

Difficulty ★☆☆☆☆Size ~8 cmIdeal 12〜28℃No heater needed

Care notes

Feeding: Eats leftovers on the bottom and sinking food.
Water: Tough and fine with a little dirt.
Temperature: Survives winter without a heater — great for an outdoor lily bowl.
Breeding: Rarely breeds at home.
Common problems: A yellow-to-orange color variety of the weather loach. It stands out on dark substrate.

Nishikigoi (koi)

Cyprinus rubrofuscus var.

Native to: Japan (Niigata, bred variety)

Difficulty ★★☆☆☆Size ~60 cmIdeal 10〜28℃No heater needed

In the game, keep it in the garden pond.

Care notes

Feeding: Floating koi food once or twice a day. Once they know you, they gather at the edge and gape for food. In winter, when the water drops below 10°C, feed sparingly.
Water: Big fish that make a lot of waste. Keep numbers suited to the pond size. Green water comes easily in summer, so thin it with water changes.
Temperature: Lives outdoors in a pond all year with no heater. In winter it rests still on the bottom, waiting for spring.
Breeding: In early summer (May–June) they lay eggs on plants. Young inherit their parents’ variety, but no two are ever patterned alike.
Common problems: Kohaku, Taisho Sanke and Showa Sanke are the “big three” of koi, judged by the beauty of their pattern from above. In a large pond they grow to about 60cm.

Wakin goldfish

Carassius auratus

Native to: Japan (close to the original goldfish)

Difficulty ★☆☆☆☆Size ~14 cmIdeal 12〜28℃No heater neededSchooling

Care notes

Feeding: Goldfish food once or twice a day. Eats well and grows well.
Water: Hardy and fine with a little dirt. Lovely swimming in a group in a pond or big bowl.
Temperature: Survives winter without a heater. An outdoor pond classic.
Breeding: Lays eggs on plants in spring. Breeds readily in a pond.
Common problems: The toughest goldfish, familiar from festival goldfish scooping. Its red-and-white pattern glows on the water.

Shubunkin

Carassius auratus var.

Native to: Japan (selectively bred)

Difficulty ★☆☆☆☆Size ~13 cmIdeal 12〜28℃No heater needed

Care notes

Feeding: Goldfish food once or twice a day.
Water: Hardy and easy. Its long tail is beautiful in a roomy pond.
Temperature: Survives winter without a heater.
Breeding: Lays eggs on plants in spring. Every youngster has its own pattern.
Common problems: A bluish body mottled with red, black and white — the “calico” pattern. From above it looks like a little cousin of the koi.

ShrimpShrimp

Small shrimp that graze on algae and leftover food.

Cherry Shrimp

Neocaridina denticulata

Native to: Japan

Difficulty ★☆☆☆☆Size ~3 cmIdeal 18〜26℃No heater needed

Care notes

Feeding: Eats algae and leftovers. Add a little shrimp food.
Water: Sensitive to sudden changes. Do water changes slowly.
Temperature: Survives winter without a heater.
Breeding: Females carry eggs under their tails until baby shrimp hatch.
Common problems: Bigger fish will eat them.

Crystal Red Shrimp

Caridina cantonensis var.

Native to: Japan (selectively bred)

Difficulty ★★★★☆Size ~2 cmIdeal 20〜25℃No heater needed

Care notes

Feeding: Just a little shrimp food. Leftovers foul the water.
Water: Very sensitive to water changes. Keep on aqua soil and change water a little at a time.
Temperature: Can't take the heat — keep below 25℃.
Breeding: The red-and-white pattern was bred in Japan. Better patterns fetch higher prices.
Common problems: Summer heat and sudden water changes. Bigger fish will eat them.

Amano shrimp

Caridina multidentata

Native to: Japan

Difficulty ★☆☆☆☆Size ~4 cmIdeal 18〜27℃No heater needed

Care notes

Feeding: The best algae eater of all. Needs only a little food.
Water: Sensitive to sudden changes. Acclimate slowly.
Temperature: Survives winter without a heater.
Breeding: Its young grow up in the sea, so it won’t breed in a tank or bowl.
Common problems: Bigger than cherry-type shrimp and eats even hair algae. Greedy — it may run off hugging a big pellet.

Large fishLarge fish

Fish that grow big — they need a 90 cm or 120 cm tank in the game.

Saddled Bichir (Polypterus endlicheri)

Polypterus endlicheri

Native to: Africa (Nile and other rivers)

Difficulty ★★☆☆☆Size ~45 cmIdeal 24〜29℃Needs a heater

In the game, it needs a 90 cm tank or larger.

Care notes

Feeding: Sinking carnivore food once a day. Feeds most actively at night.
Water: Very hardy. Produces a lot of waste, so use strong filtration.
Temperature: About 26℃ with a heater.
Breeding: Does not breed in a home aquarium.
Common problems: A "living fossil" unchanged since the age of dinosaurs. Eats any small fish that fits in its mouth. It can squeeze out through gaps, so use a lid. Needs a 90cm tank or larger.

Silver Arowana

Osteoglossum bicirrhosum

Native to: South America (Amazon)

Difficulty ★★★☆☆Size ~60 cmIdeal 25〜29℃Needs a heater

In the game, it needs the 120 cm tank.

Care notes

Feeding: Floating carnivore sticks once or twice a day. Scoops food off the surface from below.
Water: A big fish with a big bioload. Strong filtration and frequent water changes.
Temperature: 26–28℃ with a heater.
Breeding: Males brood the eggs and fry in their mouths (does not breed in home tanks).
Common problems: Grows to about 60cm, so it needs a 120cm tank or larger. It jumps, so a lid is a must. It eats anything that fits in its mouth, so keep it alone.

Asian Arowana (Super Red)

Scleropages formosus (Super Red)

Native to: Southeast Asia (Borneo)

Difficulty ★★★★☆Size ~60 cmIdeal 26〜30℃Needs a heater

In the game, it needs the 120 cm tank.

Care notes

Feeding: Floating carnivore sticks once or twice a day.
Water: Sensitive to dirty water. Frequent water changes make its big scales shine.
Temperature: Keep warm at 27–29℃ with a heater.
Breeding: Its large scales turn deeper red over the years. Full color can take several years.
Common problems: Called the "dragon fish" — one of the finest Asian Arowanas. A 120cm tank and a lid are required. Keep it alone.

Asian Arowana (Crossback Golden)

Scleropages formosus (Crossback Golden)

Native to: Southeast Asia (Malay Peninsula)

Difficulty ★★★★☆Size ~60 cmIdeal 26〜30℃Needs a heater

In the game, it needs the 120 cm tank.

Care notes

Feeding: Floating carnivore sticks once or twice a day.
Water: Sensitive to dirty water. Frequent water changes make the gold shine brighter.
Temperature: Keep warm at 27–29℃ with a heater.
Breeding: "Crossback": the gold scales reach over the back to the other side.
Common problems: Gleaming gold from head to tail — the Super Red's equal among Asian Arowanas. A 120cm tank and a lid are required. Keep it alone.

Set up your first tank

Free in your phone or PC browser. No install, no sign-up.

Go to the tank room