Albino Rainbow Shark / Red-Finned Shark (Epalzeorhynchos frenatum)

Albino Rainbow Shark at a glance

The Albino Rainbow Shark, also sold as the albino Red-Finned Shark, is the pale ornamental form of Epalzeorhynchos frenatum, a river fish from mainland Southeast Asia. It is not a shark at all. It belongs to Cyprinidae, the carp and minnow family, and takes the name from its pointed snout, tall dorsal fin and quick, purposeful swimming.

Each purchase is one live fish in the size you choose. The juveniles are slim and often shy, but this species grows to about 15 cm and becomes increasingly territorial as it matures. Buying one is really a decision about the aquarium it will live in as an adult: a long tank with a base of at least 120 × 45 cm, plenty of cover, and companions robust enough to hold their own.

The albino form swaps normal pigment for a creamy white body, red fins and red eyes, which stand out well against dark wood and stone. It is widely kept, and it is often sold as an algae-eater. It does graze, but it is better chosen as a characterful centrepiece for the lower half of a large aquarium than as a cleaning crew.

In the trade you may also meet the label Labeo frenatus. The accepted scientific name is Epalzeorhynchos frenatum, and Seriously Fish lists Labeo erythrura, a name first given to a very colourful wild form, as a junior synonym. Whatever the label, it is the same species with the same care needs.

Before you order

• An aquarium with a base of at least 120 × 45 cm, already running and matured, with ammonia and nitrite reading zero.
• A filter and heater sized for that tank, able to hold 24–26 °C with plenty of oxygen and moderate flow.
• Caves, wood and rockwork spread along the whole length of the tank.
• Active, robust companions, and no other Epalzeorhynchos, Crossocheilus, Garra or Gyrinocheilus.
• Someone at home on delivery day, ready to film the unboxing.

Sizes, sex and what you receive

There are four dispatch sizes: 3–4 cm, 4–5 cm, 5.5–7 cm and 7–8 cm. The size you select is the size supplied, not the adult size. Even the largest choice is only about half of the length this fish can reach, so plan the aquarium around the adult rather than the juvenile in the bag. The product page shows which sizes can be ordered when you buy.

Size also changes how the first months look. Seriously Fish notes that small specimens tend to hide away much of the time, while growing fish become more and more territorial. A 3–4 cm or 4–5 cm fish gives you a long, gentle run-in while it gains confidence. A 5.5–7 cm or 7–8 cm fish is nearer the stage at which it starts claiming ground, so the layout and companions need to be right from the first day.

Sex is guaranteed only when the selected option explicitly states male or female. This Albino Rainbow Shark / Red-Finned Shark listing has no sex-guaranteed option. Juveniles of this species cannot be sexed reliably, so no size is sold as a guaranteed male or female.

Gallery images have been digitally enhanced to improve image quality. Natural colour, pattern, size and maturity can vary between live animals. The fish you receive will be a juvenile at the size you selected, so expect a slimmer, younger-looking fish than a mature adult.

This species sits in our loaches and oddball fish collection alongside bottom-orientated fish with very different sizes and temperaments, so use that range for ideas rather than as a list of ready-made companions.

Where it comes from

FishBase records Epalzeorhynchos frenatum from the Mekong, Chao Phraya and Xe Bangfai basins, and from the Maeklong basin, in mainland Southeast Asia. It is a benthopelagic freshwater fish, living close to any solid surface at midwater and bottom depths in streams and rivers, and it has been observed over sandy ground. It also moves into seasonally flooded habitats and returns to the rivers as the floodwaters recede. The species is listed as Least Concern by the IUCN.

That background explains most of what the aquarium needs:

• Surfaces to graze: its natural food is the algae and periphyton that grow on solid surfaces, so rock and wood are feeding stations as well as decoration.
• Clean, moving water: it comes from flowing rivers, which is why it copes poorly with accumulating organic waste and appreciates good oxygen levels.
• Room in two directions: it uses both the bottom and the middle water, so it needs swimming length as well as floor space.

Aquarium size and layout

Floor area is the figure to plan around. Seriously Fish treats an aquarium base of 120 × 45 cm, roughly 243 litres, as the smallest to consider for a single specimen and says a group needs larger quarters. FishBase also gives 120 cm as the minimum aquarium size for the species. The OATA care sheet for freshwater sharks mentions at least 120 litres for rainbow and red-tailed black sharks, but that is a general figure for the group; the longer species footprint is the better plan for an adult fish.

Build a flowing-river layout

Seriously Fish suggests an aquarium designed to resemble a flowing river, which suits a fish from streams and rivers well:

• Substrate: sand or smooth fine gravel across the open feeding areas, which the OATA sheet recommends so freshwater sharks do not injure their sensitive barbels.
• Stone: variably sized rocks and a few larger water-worn boulders for structure and grazing surfaces.
• Wood: driftwood roots and branches to create overhangs, caves and territory boundaries.
• Plants: Microsorum, Bolbitis or Anubias grown attached to the wood and stone. This species should not harm softer-leaved plants either.
• Light: bright lighting encourages algae and the small organisms that grow with it, which gives the fish something natural to graze.

Cover and territory

Seriously Fish describes this species as relatively unfussy about décor provided there is enough cover. Spread several caves, wood overhangs and planted areas along the full length of the tank rather than clustering them at one end. That gives the rainbow shark a home base and gives other fish their own places to retreat, which matters more as it grows into its territorial adult stage. Leave open water along the front and middle for swimming.

A long tank also helps the whole community. The OATA sheet points out that larger aquariums keep temperature and water quality more stable, and a longer tank gives a territorial fish and its neighbours more room to keep apart.

Water, oxygen and filtration

The routine targets below are the band where the species profile, the FishBase species data and the OATA sheet for freshwater sharks agree. Stability matters more than chasing an exact number.

Why 24–26 °C

Seriously Fish gives 20–26 °C for aquarium keeping, and the OATA sheet gives 22–27 °C as a general range for freshwater sharks. FishBase records 24–27 °C for the species in its natural environment, which describes the rivers rather than a tank setting. Holding the aquarium at 24–26 °C keeps you inside all three. For pH, Seriously Fish says the fish is happy within 6.5–8.0 but that a value close to neutral is usually recommended. For hardness, Seriously Fish gives a wide 2–15 dGH; FishBase's 5–12 dH and the OATA group figure of 4–12 °dH narrow that to a comfortable 5–12 dGH.

Oxygen, flow and filtration

Like many fish from running water, this species is quite intolerant of accumulating organic waste and does best with a high level of dissolved oxygen and moderate water movement. For a tank of around 243 litres, Seriously Fish's rule of thumb is a turnover of four to five times the tank volume an hour, which means a filter rated at roughly 970–1,215 litres per hour, and about 125–175 W of heating in a room at around 20 °C.

A filter is essential whatever the tank size. As the RSPCA guidance on aquarium filters explains, fish release ammonia, which is toxic; beneficial bacteria in a working biological filter convert it to nitrite, which is also toxic, and then to nitrate, which is safer. The OATA sheet adds that freshwater sharks can be stressed by even the smallest amounts of ammonia, so a fully matured filter is the foundation of keeping this fish well.

Testing your water

If you are unsure what each reading means, our guide to aquarium water parameters explains what to test and why. You can also enter your own results in the water parameter matcher to see how your tap and tank water compare with these targets before the fish arrives.

Feeding a grazing omnivore

FishBase describes the natural diet as algae, periphyton, phytoplankton and some zooplankton. Seriously Fish calls the species primarily an aufwuchs grazer: it rasps the film of algae and tiny animals from rocks and wood, and in the wild also takes small crustaceans and insect larvae. In the aquarium, the aim is to recreate that mix of plant matter and small animal foods.

What to offer

• Everyday food: sinking pellets with a high algae content, as the OATA sheet suggests for rainbow sharks, plus good quality dried flakes or granules.
• Small frozen or live foods: bloodworm (chironomid larvae), Daphnia and Artemia bring out the best colour and condition, according to Seriously Fish. Freeze-dried bloodworm and Artemia are convenient alternatives.
• Fresh plant material: shelled peas, cucumber, blanched courgette, spinach and small pieces of chopped fruit.
• Natural grazing: biofilm and algae on stones and wood, encouraged by bright lighting.

How much to feed

The OATA sheet for freshwater sharks recommends feeding only what the fish can eat within a few minutes, once a day, and warns against overfeeding because uneaten food breaks down and releases toxic waste into the water. Take out any vegetable pieces that have not been eaten before they start to break down. Once it has settled, this fish will often rise into midwater to feed and to browse the film on rockwork, so food does not have to land right under its nose.

It is not an algae-control fish

This species is often sold as an algae-eater. It does browse algae, but Seriously Fish notes that it does not do so as effectively as some Crossocheilus species and that there is little point in buying it for that purpose. Treat grazing as a bonus, feed it properly, and choose it because you want the fish itself.

Feeding in a busy community

The companions that suit a rainbow shark best, such as danios, barbs and rainbowfish, are quick feeders in open water. Sinking pellets, wafers of algae-based food and vegetable pieces give the rainbow shark its own share at the level where it prefers to graze, while flakes and granules go to the fish higher up. Watch at feeding time for the first few weeks to be sure the new fish is actually eating, especially a small juvenile that is still spending much of the day in cover.

Weekly maintenance and stocking

Good husbandry is essential for freshwater sharks, and a steady weekly routine does most of the work. The OATA care sheet for freshwater sharks sets out the basics:

• Carry out a 25% partial water change at least once every week, using a siphon to lift solid waste from the gravel or sand.
• Test the water regularly, at least once per week, so ammonia and nitrite never build up.
• Keep nitrate to no more than 20 mg per litre above your normal tap water level; the weekly change is the main way to hold it there.
• Treat all replacement water with a tap water conditioner to remove chlorine or chloramine before it goes into the aquarium.
• Check the filter for blockages. If the media needs cleaning, never run it under the tap, because chlorine or chloramine can kill the beneficial bacteria. Rinse it lightly in the tank water you have just removed instead.

Stock the aquarium slowly

Filter bacteria need time to catch up whenever you add fish and feed more. Adding too many fish at once, or stocking a new aquarium too quickly, can cause new tank syndrome: there are not enough nitrifying bacteria to deal with the extra waste, ammonia and nitrite rise, and fish can become ill or die. Before adding any fish, check that ammonia and nitrite read zero. If this will be your first tropical aquarium, our guide to setting up a first tropical tank walks through setting up and maturing the tank properly before any livestock arrives.

Arrival day and the first weeks

Every order is hand-packed by our team. Fish are bagged in pure oxygen and packed in an insulated poly box, with a heat pack when the weather calls for it, then carried by a tracked, licensed live-animal courier. We email the tracking number and your confirmed delivery date so you know when to be in. The full details are on our delivery and Live Arrival Guarantee page.

Before delivery day

Have the aquarium ready before the fish is ordered, not on the morning it arrives:

• The heater has been holding a steady 24–26 °C for several days.
• A fresh test shows ammonia and nitrite at zero, which the OATA sheet asks you to confirm before adding any fish.
• Caves, wood and plants are in place, so the new fish has somewhere to settle straight away instead of having to compete for cover.
• Tap water conditioner is to hand, along with a spare bucket for water changes in the first weeks.

On arrival day

1. Make sure someone is at the delivery address to receive the parcel, because live fish cannot be left unattended.
2. Before the parcel is opened, start one continuous unboxing video that shows the sealed outer box, the opening, and the fish still inside the sealed bag.
3. Float the sealed bag in your aquarium for 20–30 minutes, acclimatising the fish slowly before releasing it.
4. Release the fish into the aquarium without pouring the bag water into your tank.
5. If anything has gone wrong, contact us the same day with your order number and the unboxing video. WhatsApp is the fastest way, and we will arrange a replacement or refund.

The Live Arrival Guarantee needs someone at the address to receive the parcel, the parcel opened and inspected on the day it arrives, and a continuous unboxing video showing the parcel still sealed at the start.

The first weeks

Expect a small rainbow shark to spend a lot of time hidden at first; that is normal for young fish of this species. Seriously Fish notes that once settled it often moves up into midwater to feed and graze, and it will gradually become bolder and start to patrol a favourite area. Keep the rest of the aquarium routine steady and watch how it and the other fish interact as it grows.

A healthy fish has clear bright eyes, undamaged fins, intact scales, no ulcers or bumps and normal swimming behaviour. Those are the things to check once it is out of the bag and exploring.

Health, growth, sexing and breeding

All fish vary slightly in behaviour and appearance, so learn what is normal for yours and look for changes. The OATA sheet lists the signs worth watching:

• Swimming: hanging at the surface, sitting on the bottom or erratic swimming.
• Colour: turning darker or paler than normal.
• Temperament: a change in aggression or much more hiding than usual.
• Breathing: gill covers moving faster or slower than normal.
• Appearance: white spots, fluffy growths, or lost fins or scales.
• Condition and feeding: weight loss or gain, reduced appetite or no interest in food.

If you are worried about any fish, test the water quality first. Poor water is a common trigger, and rainbow sharks are sensitive to ammonia and organic waste. Then get in touch for further guidance.

Growth and long-term planning

Freshwater sharks generally grow quite slowly, according to the OATA sheet. That slow growth is one reason juveniles end up in tanks that are too small: a small juvenile can look settled for a long time before the adult size and temperament arrive. Seriously Fish observes that this species is rarely kept in ideal conditions and that juveniles are often sold with little information about temperament or eventual size. Buying one is a long-term commitment, and the right aquarium from the start saves a difficult rehoming later.

Sexing

According to Seriously Fish, sexually mature females are noticeably thicker-bodied than males, but it is impossible to sex juveniles accurately. The fish you receive will be a juvenile, so its sex will not be known when it arrives.

Breeding

As far as Seriously Fish knows, this species has not been bred in private aquaria. The large numbers seen in the hobby are produced on fish farms for the ornamental trade with the aid of hormones. The albino is an ornamental variant that has become extremely popular in the hobby. A home aquarium should be planned for one fish to live out its life, not for spawning.

How temperament changes with age

Temperament is the part of this fish that catches people out. The OATA sheet describes rainbow sharks as reasonably peaceful when younger, becoming more aggressive and territorial as they grow. Seriously Fish adds that it becomes increasingly territorial with growth and can show particularly high levels of aggression towards similar-looking species.

• Juveniles: shy, often hidden, and unlikely to cause trouble in a well-planned tank.
• Growing fish: start to claim a favourite cave, wood overhang or stretch of substrate, and chase fish that come too close.
• Adults: hold a territory and are hardest on anything with a similar shape or look.

Individuals also differ. Some are more belligerent than others, and Seriously Fish mentions reports of apparent alliances with other species such as the clown loach, Chromobotia macracanthus. It is not known whether those behavioural differences relate to sex.

The practical rule is to plan for the adult. A mix that works while the rainbow shark is 4 cm long may not work once it is nearly full grown and holding the best cave in the tank. Keep one per aquarium in most homes, give it room and cover, and be prepared to rehome or separate a fish that keeps harassing its tank mates.

Choosing tank mates

Seriously Fish rates this species as a slightly better community choice than its relative, the red-tailed black shark Epalzeorhynchos bicolor, but says tank mates must still be chosen with care. Here is how the main groups of fish work out.

Good choices

• Active, slightly larger and robust species such as danios, barbs and rainbowfish, which the OATA sheet names for rainbow sharks.

Choose with care

• Loaches from the genera Botia, Chromobotia, Syncrossus and Yasuhikotakia. Seriously Fish reports that Epalzeorhynchos species seem to leave them in peace, but not every loach can be housed with every other loach, so research each species properly first.

Leave out

• Other Epalzeorhynchos, including the red-tailed black shark and, in most tanks, a second rainbow shark.
• Crossocheilus, Garra and Gyrinocheilus species, which tend to be attacked constantly. That includes the familiar algae-eaters sold under those names.
• Smaller, slow or delicate fish. The OATA sheet advises mixing rainbow sharks only with active, slightly larger and robust species.

Keep a close eye on companions that use the bottom of the tank. Anything that competes for the same caves or grazing surfaces is more likely to be treated as a rival than a fish that spends its time in open water.

Size matching

The OATA sheet asks for companions that are slightly larger than the rainbow shark, not smaller. A fish that is already bigger than it is far less likely to be pushed around, while very small fish have nowhere to go once a territorial adult claims the lower half of the tank. Remember that the rainbow shark itself keeps growing towards 15 cm, so judge companions against the adult size rather than against a 4 cm juvenile.

Plants and décor

Planted aquariums are no problem. Seriously Fish says this species should not harm softer-leaved plants, and epiphytes such as Microsorum, Bolbitis and Anubias attached to wood and stone suit the river-style layout well. The plants and hardscape double as the cover that lets other fish break contact with a patrolling rainbow shark.

Watch the whole community

Bullying often shows up first in the fish being bullied. The warning signs the OATA sheet lists for any fish apply here: a tank mate hiding far more than normal, damaged or missing fins, a fall in appetite or body condition, or faster breathing. Check the rainbow shark's own temperament as well; a change in its level of aggression is one of those signs too. If one fish is being pinned down repeatedly, test the water first, then be ready to separate or rehome the fish involved rather than waiting for the situation to settle on its own.

Albino Rainbow Shark questions

How big does the Albino Rainbow Shark / Red-Finned Shark grow?

Plan for a fish of about 15 cm. FishBase gives a maximum length of 15 cm and Seriously Fish gives 150 mm, so the adult will be about double the length of the largest juvenile size and five times the smallest. It grows quite slowly, which makes it easy to underestimate, so set up the aquarium for the adult from the start.

What size aquarium does it need?

For one adult Epalzeorhynchos frenatum, plan an aquarium with a base of at least 120 × 45 cm, which Seriously Fish calculates at around 243 litres. Length and floor area matter most for a fish that patrols the lower levels, and a group needs a larger aquarium than that minimum.

Can I keep more than one rainbow shark together?

In most home aquariums, keep one. This species directs its strongest aggression at similar-looking fish, members of its own genus are among the fish it attacks most, and Seriously Fish treats a group as something for larger quarters than the single-fish minimum.

Is the Albino Rainbow Shark / Red-Finned Shark suitable for beginners?

Only for a beginner who already has a long, mature and stable aquarium. Freshwater sharks are usually undemanding about water chemistry, but this one needs a 120 cm tank, grows territorial and must be matched with robust companions. For a small starter aquarium, choose a different fish.

What does Epalzeorhynchos frenatum eat, and will it clear algae?

It is an omnivorous grazer. Offer sinking pellets with a high algae content and good dried granules or flakes, rotate small frozen or live foods such as bloodworm, Daphnia and Artemia, and add fresh vegetables such as shelled peas, cucumber, blanched courgette or spinach. It browses algae and biofilm but is a poor choice if algae control is the main reason for buying.

What temperature and pH does it need?

Aim for 24–26 °C, pH 6.5–8.0 with a value close to neutral usually recommended, and general hardness of 5–12 dGH. Those routine targets sit inside the ranges given by FishBase, Seriously Fish and the OATA care sheet for freshwater sharks as a group.

Is it aggressive?

Young Epalzeorhynchos frenatum are fairly peaceful and often shy, but they become increasingly territorial as they grow. The aggression is aimed mainly at similar-looking fish, some individuals are more belligerent than others, and slow or delicate companions are a poor match.

Which fish can live with it?

The OATA care sheet suggests active, slightly larger and robust species such as danios, barbs and rainbowfish. Seriously Fish reports that Botia, Chromobotia, Syncrossus and Yasuhikotakia loaches are usually left in peace, although not every loach can share a tank. Other Epalzeorhynchos, and Crossocheilus, Garra and Gyrinocheilus algae-eaters, tend to be attacked constantly, so leave them out.

How does the Albino Rainbow Shark / Red-Finned Shark arrive alive in the UK?

It is hand-bagged in pure oxygen, packed in an insulated poly box with a heat pack when the weather calls for it, and carried by a licensed live-animal courier, so someone must be in to receive it. Before opening, start a continuous unboxing video showing the sealed parcel, the opening and the fish still in the sealed bag; this is needed for any Live Arrival Guarantee claim. Then float the bag for 20–30 minutes before releasing the fish, without adding the bag water to your tank.

Sources

• FishBase species summary for Epalzeorhynchos frenatum: accepted name, family, distribution, wild habitat and diet, the recorded environmental temperature, pH and hardness, and the 15 cm maximum length.
• Seriously Fish species profile: aquarium size, layout, water values, diet, behaviour, tank mates, sexing and breeding for this species.
• OATA care sheet: how to look after freshwater sharks: UK trade-body guidance for freshwater sharks as a group, covering water, aquarium size, maintenance, health checks, feeding and compatibility.
• RSPCA aquarium environment advice: general welfare guidance on filtration and the nitrogen cycle.
• Tropical Fish Co delivery and Live Arrival Guarantee page: packing, courier, arrival and claim steps.