Featherfin Synodontis (Synodontis eupterus)

Meet a substantial African river catfish

The Featherfin Synodontis (Synodontis eupterus), also called the featherfin squeaker, is a freshwater mochokid catfish from Africa’s White Nile, Niger, Volta, Chad, Kwa Ibo and Cross basins. FishBase records a maximum of 30 cm standard length. It suits a keeper prepared to plan a mature, filtered aquarium around that adult size rather than around the much smaller fish that may arrive.

This is a benthopelagic species, meaning that its activity is associated with the lower part of the water column and the bottom. FishBase records it over muddy bottoms and rocks in the wild and identifies it as an upside-down species. Those details make lower-level space, accessible shelter and deliberate feeding more important than choosing it simply as a decorative addition.

The high, feather-like dorsal fin is central to the common name. A Wikipedia account of its natural history also explains that featherfin squeakers can make noises to communicate with one another. These are features of the species, but they do not determine sex, social requirements or compatibility with another fish.

Plan for the recorded maximum

The decisive planning figure is 30 cm standard length. Standard length excludes the tail, so the complete fish requires more room than a simple 30 cm object. Before choosing it, check that the aquarium can accommodate the adult body, an accessible refuge, an effective biological filter and unobstructed routes around the lower level.

FishBase describes a wild diet based mainly on insect larvae with algae also taken. Aquarium feeding should therefore be deliberate and species-appropriate; this catfish must not be treated as a clean-up animal that survives on whatever other fish leave behind.

Choose the dispatch size without confusing it with adult size

One purchase supplies one Featherfin Synodontis from the selected size. Use the live size selector to choose from the labels 2 - 3 cm, > 7 cm, 4-4.5 cm, 5-6 cm and 20-25 cm. The size you select is the size supplied, not the adult size.

Every selection needs an aquarium planned around the 30 cm adult maximum. A smaller dispatch fish does not make a small aquarium a suitable long-term home, while the 20-25 cm grade already needs routes and shelter sized for a substantial catfish. Check the aquarium itself rather than using the dispatch label as a space recommendation.

Understand what the offer includes

• Purchase unit: one live fish per purchase.
• Dispatch size: the size named by the selected label.
• Adult planning size: 30 cm standard length.
• Sex: Sex is guaranteed only when the selected option explicitly states male or female. This Featherfin Synodontis listing has no sex-guaranteed option.

Do not infer sex, age or origin from the selected size. A length label describes the fish’s dispatch size and nothing more.

The gallery images are representative of this type of animal rather than photographs of the exact animal supplied, so colours can look slightly different from the live animal.

The gallery shows the characteristic body and dorsal-fin profile for identification and visual reference. It does not turn visible markings, body proportions or apparent sex into a promise about the individual fish dispatched.

Decide whether its adult needs fit your aquarium

Choose this catfish when you can provide a well-matured, filtered freshwater aquarium, keep the routine water within the FishBase–OATA overlap, feed an appropriate sinking diet and reserve enough lower-level space for a 30 cm adult. Delay the purchase if the aquarium is newly set up, unfiltered or planned only around the selected dispatch size.

A mature aquarium means that the biological filter has established the bacteria needed to process fish waste. Maturity is not achieved simply by filling the aquarium and bringing it to temperature. Ammonia and nitrite must both test at zero before the fish is introduced.

If another catfish would suit the plan better, browse the catfish and plecos collection. Compare adult size, water range, diet and social needs separately rather than treating members of a broad retail category as interchangeable.

Plan the aquarium around the 30 cm adult

Plan every dimension and lower-level route around a Featherfin Synodontis reaching 30 cm standard length. FishBase also reports a recorded specimen length of 22.2 cm, but the 30 cm maximum remains the figure to use for the long-term aquarium, shelter and access routes.

OATA’s freshwater-catfish guidance recommends an aquarium of at least 80 litres for a shoal of smaller species such as Corydoras or for smaller plecos, then says much larger aquariums are needed for bigger species. A Featherfin Synodontis reaching 30 cm belongs in that larger-species decision, so do not use the 80-litre small-catfish benchmark for this fish.

Check usable space rather than the label on the aquarium

• Mark out 30 cm: hold a ruler against the aquarium to visualise the standard-length maximum, remembering that the tail extends beyond it.
• Inspect the lower level: make sure decor does not divide the bottom into passages that an adult cannot use.
• Measure each refuge: wood, pots or caves must remain accessible as the body and dorsal fin grow.
• Allow for equipment: internal filters, heaters and decor reduce usable water and movement space.
• Assess the whole stocking plan: every additional animal adds waste and uses part of the aquarium’s space.

Use the adult measurement for the first layout, not as a future upgrade target. Moving a substantial catfish later can be avoided by preparing the final-scale aquarium before introduction.

A larger water volume also changes more slowly than a smaller one, helping temperature and water quality remain stable. Volume alone is not enough, however: the fish still needs usable lower-level routes, shelter and filtration that can process the aquarium’s total waste load.

Keep the water within the FishBase–OATA overlap

Keep the Featherfin Synodontis at 22–26°C, pH 6.2–7.5 and 4–15°dH. Temperature and pH are the overlap between FishBase’s species environmental range and OATA’s freshwater-catfish group guidance. The hardness range uses OATA’s 4°dH lower guide and FishBase’s 15°dH upper record; it is not a species-specific optimum.

Choose a stable point inside each range instead of allowing conditions to move repeatedly between the limits. A reading of 24°C and pH 7.0, for example, sits inside both stated ranges. That example is a way to check a measured result, not a requirement to alter stable water that already falls within the full range.

Use measurements to make the decision

Read the water chemistry guide before changing pH or hardness. Test both the aquarium and its replacement water so that a correction does not create a sudden swing.

Use the water matcher to compare measured values with 22–26°C, pH 6.2–7.5 and 4–15°dH. If a result falls outside the range, identify whether the aquarium, source water or maintenance routine has changed before adding the fish.

Establish biological filtration before introduction

Use a well-set-up and maintained biological filter. The RSPCA explains that fish release toxic ammonia, which filter bacteria convert first to nitrite and then to the safer nitrate. The aquarium is not ready for this catfish until both ammonia and nitrite test at zero.

A filter is essential regardless of aquarium size. It must remain running and able to process the total waste created by all fish and feeding in the aquarium. Adding several animals quickly or increasing food sharply can leave the established bacterial population unable to process the new load.

Prepare in a measurable order

1. Set up the aquarium, heater and filter before planning the fish’s arrival.
2. Allow the biological filter to mature and confirm its progress with water tests.
3. Check that ammonia and nitrite are both 0 mg/l.
4. Check temperature, pH and hardness against the stated range.
5. Add fish slowly rather than increasing the aquarium population all at once.
6. Continue testing after introduction so that a change is detected before it becomes a health problem.

OATA calls the ammonia and nitrite rise caused by insufficient nitrifying bacteria “new tank syndrome”. It can make fish ill or cause death, so visual clarity is not a substitute for a test result. Clear water can still contain ammonia or nitrite.

Follow the first tropical aquarium guide when preparing a new system. For an established aquarium, confirm that the filter is operating normally and that adding another fish will not be combined with several other changes to stocking or feeding.

Keep the filter running through routine maintenance. Clean it only when needed and preserve its bacterial media using the water-change method described below.

Feed sinking food that reflects the recorded diet

Feed a suitable sinking food based primarily on insect or other invertebrate ingredients, with algae represented in the diet. FishBase records that wild Featherfin Synodontis feed mainly on insect larvae and also take algae. That biology should determine the main food rather than the idea that every catfish can live on leftovers.

OATA advises feeding catfish the appropriate sinking food once a day and offering only what they can eat within a few minutes. This fish must receive its own food at the lower level; food eaten elsewhere in the aquarium does not show that the catfish has fed.

Use a simple daily feeding check

• Place the food deliberately: make sure it reaches an area the catfish can access.
• Watch for a few minutes: confirm that the intended fish finds and eats it.
• Remove the excess: do not leave uneaten food to break down in the aquarium.
• Adjust the next portion: reduce it when food remains after the feeding period.
• Keep the diet aligned: choose sinking food whose ingredients cover the recorded insect-larva and algae diet.

Uneaten food releases waste as it breaks down, increasing the work required from the biological filter. A larger portion is therefore not a substitute for observing access. Feed enough for the fish to eat within the stated few-minute period, then use body condition and continued interest in food as part of routine observation.

Changes in feeding can be an early warning. OATA recommends watching for reduced intake or loss of interest in food alongside changes in swimming, colour, breathing and body condition. If appetite changes, test ammonia and nitrite before assuming that the food itself is the only cause.

Do not use this catfish as an aquarium-cleaning method. Its recorded diet and daily feeding requirement remain the same even when other fish drop food to the bottom.

Create shelter without blocking lower-level routes

Provide accessible shelter in the form of wood, suitable pots or caves while preserving clear routes around the aquarium’s lower level. OATA notes that many catfish appreciate these forms of cover. Size each opening and route for the 30 cm adult rather than for the dispatch-size fish.

FishBase records the wild species over muddy bottoms and rocks and describes it as benthopelagic. Use that natural history to understand why the bottom and lower water column matter, but keep the aquarium layout practical: the fish must be able to enter, leave and move between the spaces provided.

Review the layout from the fish’s level

• Look along the bottom and identify every route narrowed by wood, pots, rocks, equipment or plants.
• Check that the dorsal fin will not prevent an adult from using the chosen refuge.
• Keep access to sinking food separate from inaccessible gaps where uneaten food could collect.
• Leave the filter intake and outlet free from decor that would obstruct normal operation.
• Recheck the layout as the fish grows rather than assuming the juvenile arrangement remains suitable.

Live plants can provide cover, although OATA notes that some catfish may eat or dig them up. Treat planting as part of the layout to monitor, not as a substitute for wood, pots or caves. Plastic plants and suitable ornaments are alternatives when live plants do not remain practical.

The gallery scene shows one spotted grey catfish above pale sand with plants behind it, but that image describes the scene rather than prescribing a substrate or planting scheme. Base the aquarium decision on accessible space, shelter, filtration and measurable water conditions.

Follow a weekly testing and maintenance routine

At least once every week, make a partial water change of 25%. Test ammonia and nitrite at least weekly, keep both at zero and monitor nitrate so that it does not exceed 20 mg/l above the normal tap-water level. These checks give the filter and water-change routine a measurable outcome.

Treat replacement water with tap-water conditioner to remove chlorine or chloramine before it enters the aquarium. Match its temperature closely enough to avoid a sudden change, and compare pH or hardness whenever the source water or treatment method has changed.

Protect the biological filter during cleaning

1. Check the filter for blockages during the weekly routine.
2. Remove aquarium water as part of the partial water change.
3. If the filter needs cleaning, rinse its media lightly in that removed aquarium water.
4. Do not run it under the tap because chlorine or chloramine may kill the beneficial bacterial population.
5. Restart the filter and confirm that normal flow has resumed.

Use a siphon when needed to remove solid waste from the bottom, especially around feeding areas and decor where sinking food can collect. Removing waste supports the filter; it does not replace the water tests or the partial change.

Respond to changes rather than waiting

Observe swimming, colour, temperament, breathing, appearance, body condition and feeding. Warning changes include hanging at the surface, erratic swimming, becoming darker or paler, hiding more than normal, slower or faster gill movement, white spots, fluffy growths, loss of fins or scales, weight change and reduced feeding.

If any of these changes appear, test water quality first and contact us for health guidance. Record the ammonia, nitrite, nitrate, temperature and pH results so that the next decision starts with measurements rather than guesswork.

Follow the arrival sequence before release

Be present to receive the parcel. The fish is hand-bagged in pure oxygen, placed in an insulated box and accompanied by a heat pack when the weather calls for it. A licensed live-animal courier carries the parcel, and it must not be left unattended.

Follow the Tropical Fish Co delivery and Live Arrival Guarantee policy in this order:

1. Receive the parcel in person. Someone must be at the delivery address when it arrives.
2. Start filming before opening. Show the parcel still sealed with the outer box visible.
3. Open and inspect it the same day. Keep the recording in one continuous take.
4. Show the fish in the sealed bag. Its condition must be visible before anything is disturbed.
5. Float the bag for 20–30 minutes. Complete this step before releasing the fish.
6. Do not pour the bag water into the aquarium. Release the fish without adding the transport water.

Keep the sealed parcel, opening and fish-in-bag stages in the same continuous recording. The video is required for a Live Arrival Guarantee claim, together with the order number. Contact us the same day if there is an arrival problem.

Check the aquarium before the parcel comes

Complete the aquarium checks separately from opening the parcel. Temperature should be 22–26°C, pH 6.2–7.5, hardness 4–15°dH, and ammonia and nitrite both 0 mg/l. Confirm that the filter is running and that the adult-scale refuge remains accessible.

After release, continue the normal observation routine. Test the water if swimming, breathing, colour or feeding changes, and avoid responding to one concern by making several unmeasured changes at the same time.

Screen every mixed community case by case

Treat every mixed community as an individual stocking decision. OATA explains that catfish range from small and peaceful to large and predatory and advises caution when mixing some species. That broad variation means the word “catfish” is not enough to establish whether two animals should share an aquarium.

Assess each proposed companion against the Featherfin Synodontis requirements: 22–26°C, pH 6.2–7.5, 4–15°dH, a mature biological filter, deliberate sinking feeding, accessible lower-level shelter and space planned around a 30 cm adult. A companion must fit the same aquarium without preventing those needs from being met.

Do not treat Corydoras, Otocinclus or smaller plecos as automatic companions merely because OATA discusses them as community catfish. Its companion comments describe those groups, not a pairing with Synodontis eupterus.

For a specific mixed plan, ask us with the aquarium dimensions, measured water values, existing livestock and adult sizes. The decision should cover the complete aquarium rather than one pair of names in isolation.

Monitor behaviour after every stocking change

Add fish slowly and observe the aquarium after every stocking change. OATA warns that increasing the population too quickly can exceed the capacity of the filter bacteria, producing unhealthy ammonia or nitrite. Compatibility therefore includes biological capacity as well as visible interaction.

Use a first-week check

• Test ammonia and nitrite and keep both at 0 mg/l.
• Confirm that the Featherfin Synodontis reaches its sinking food.
• Check that its refuge and lower-level routes remain accessible.
• Watch for changes in swimming, colour, breathing, aggression, hiding and feeding.
• Reduce avoidable disturbance while keeping the normal testing and feeding routine consistent.

A change in aggression or hiding is a reason to review the whole setup. Test the water, confirm feeding access and inspect how the layout is being used. If one animal is being harmed or prevented from meeting its care needs, separate the unsafe interaction rather than waiting for repeated injury.

Review again as the fish grows

The dispatch size is only the starting measurement. Reassess usable space, shelter entrances, food access and the filter load as the catfish approaches its 30 cm adult maximum. A community that physically fits around a small fish may require a different arrangement as that fish grows.

Do not assign a fixed group number to this species from a rule written for another catfish. OATA notes that some catfish are shoaling and others prefer to live alone. Plan any additional catfish only after checking the needs of each named animal and the capacity of the complete aquarium.

Answer the questions keepers ask before choosing

How big does a Featherfin Synodontis get?

It reaches a recorded maximum of 30 cm standard length according to FishBase. Standard length excludes the tail, so plan the aquarium, routes and shelter around a fish whose complete body extends beyond that measurement.

What size aquarium does a Featherfin Synodontis need?

Use an aquarium much larger than OATA’s 80-litre benchmark for shoals of smaller catfish and plan every dimension around the 30 cm adult maximum. Check usable lower-level routes, adult-scale shelter and filtration rather than relying on volume alone.

How many should I keep together?

Use no fixed group number for this species. OATA’s freshwater-catfish guidance says social needs range from shoaling to living alone, so assess any multi-catfish plan individually; one purchase supplies one fish.

Does a Featherfin Synodontis suit beginners?

Choose it only if you can prepare a mature, filtered aquarium, plan space around a 30 cm adult, test the water weekly and provide deliberate sinking food. No beginner rating should replace those practical checks.

What does a Featherfin Synodontis eat?

FishBase records a wild diet mainly of insect larvae with algae also taken. Feed an appropriate sinking food based primarily on insect or other invertebrate ingredients with algae represented, once daily in an amount eaten within a few minutes, following OATA’s feeding guidance.

What temperature and pH does it need?

Keep it at 22–26°C and pH 6.2–7.5, the FishBase–OATA overlap, with general hardness of 4–15°dH using OATA’s lower guide and FishBase’s upper record. Keep ammonia and nitrite at 0 mg/l.

Is a Featherfin Synodontis aggressive or a fin-nipper?

Treat it as a case-by-case community fish: OATA says catfish compatibility varies and recommends watching for changes in aggression or hiding. Monitor every interaction and separate animals if one is being harmed or prevented from feeding or using shelter.

Which animals can this fish live with?

Use no universal companion list. Screen every proposed animal against 22–26°C, pH 6.2–7.5, adult space, filtration, feeding access and shelter, and do not assume that other catfish are compatible merely because they share a retail group.

How does it arrive alive in the UK?

Start filming with the parcel still sealed before you open it or float the bag. The Tropical Fish Co policy requires someone to receive it, same-day inspection in one continuous take and the fish shown in its sealed bag; then float the bag for 20–30 minutes before release. A licensed live-animal courier carries the oxygen-bagged fish in an insulated box, with a heat pack when the weather calls for it.

References used for identity and care

• FishBase: Synodontis eupterus identity, family, African distribution, maximum length, wild environmental range, habitat and diet.
• Wikipedia: featherfin squeaker common-name context, African river basins and sound communication.
• OATA: freshwater-catfish water, aquarium, feeding, maintenance, health-observation and compatibility guidance.
• RSPCA: biological filtration and aquarium waste processing.
• Tropical Fish Co delivery policy: packing, receipt, unboxing video and acclimatisation procedure.