Upside-down catfish care guide
Also called: Upside down catfish, Blotched upside-down catfish, Upside-down synodontis
The upside-down catfish is a small, peaceful African catfish famous for swimming belly-up under leaves and wood. Keep a group of 4 or more in at least 29 gallons (110 L) with caves, and skip nano fish and shrimp.
Upside-down catfish need a tank of at least 29 gallons (110 L), a group of 4 or more, and water at 24–27°C (75–81°F) with a pH of 6–7.5. They grow to about 9.5 cm (3.7 in) and are peaceful.
Plan a tank with upside-down catfishSee all tank mates
Upside-down catfish quick facts
| Scientific name | Synodontis nigriventris |
|---|---|
| Family | Mochokidae |
| Origin | Congo River basin, Central Africa (DR Congo, Republic of the Congo and Cameroon) |
| Adult size | 9.5 cm (3.7 in) |
| Minimum tank | 29 gallons (110 L), at least 80 cm (31 in) long |
| Temperature | 24–27°C (75–81°F) |
| pH | 6–7.5 |
| Hardness (GH) | 5–15 dGH |
| Group size | 4 or more (group) |
| Temperament | Peaceful |
| Swims at | All levels |
| Diet | Omnivore |
| Care level | Moderate |
| Lifespan | 8–15 years |
| Safe with shrimp? | No, eats shrimp |
| Safe with plants? | Yes |
Tank setup
A group of four needs at least a 29-gallon (110 L) tank about 80 cm (31 in) long. Add driftwood, caves and broad-leaved plants so they can rest upside down in the shade. Dim light or floating plants help them come out during the day. Sand or smooth gravel protects their barbels.
How many upside-down catfish in a tank?
The smallest common tank that suits upside-down catfish is a 40 gallon. Here is roughly how many fit in each size when they are the only fish, based on adult size and waste output. Leave room if you want tank mates.
| Tank | Upside-down catfish (alone) |
|---|---|
| 3 gallon | Too small |
| 5 gallon | Too small |
| 10 gallon | Too small |
| 15 gallon | Too small |
| 20 gallon | Too small |
| 20 gallon long | Too small |
| 29 gallon | Too small |
| 40 gallon | 4–12 |
| 55 gallon | 4–17 |
| 75 gallon | 4–23 |
| 125 gallon | 4–38 |
What you need for upside-down catfish
Sized for a 29 gallon tank, the smallest common size that suits a group of 4 upside-down catfish. For a different tank or a mix of fish, use the stocking calculator for a list sized to your plan.
Tank and equipment
- 29 gallon aquarium (tank or kit) (opens Amazon in a new tab)Bigger tanks are more stable and easier for beginners. How to choose
- Aquarium stand for 29 gallons (opens Amazon in a new tab)The water alone weighs about 242 lb (110 kg), before glass, gravel and rock. How to choose
- Adjustable heater, 100 W (opens Amazon in a new tab)Holds about 78 °F (25.5 °C) in a room at 65 °F (18 °C). How to choose
- Aquarium thermometer (opens Amazon in a new tab)Check it daily: heaters can fail stuck on or off. How to choose
- Hang-on-back filter rated 115–175 GPH (opens Amazon in a new tab)Community tank: 4–6 times the tank volume per hour. How to choose
- About 45 lb of aquarium gravel (opens Amazon in a new tab)Enough for a layer about 2 in (5 cm) deep. Smooth gravel suits most community fish. How to choose
- Water conditioner (dechlorinator) (opens Amazon in a new tab)Removes chlorine and chloramine from tap water. Seachem Prime is a popular, concentrated choice. How to choose
- Liquid test kit (ammonia, nitrite, nitrate, pH) (opens Amazon in a new tab)Liquid kits are more accurate than strips. The API Freshwater Master Test Kit is the common choice. How to choose
- Gravel vacuum (siphon) (opens Amazon in a new tab)Cleans the gravel and does the water change in one go. How to choose
- LED aquarium light, about 30 in long (opens Amazon in a new tab)Match the light to the tank length. Basic LEDs grow easy plants. How to choose
Food and extras for upside-down catfish
- Tropical fish pellets (opens Amazon in a new tab)A good staple for medium community fish.
Product links go to Amazon search results. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Disclosure.
Water parameters
Keep the temperature steady at 24–27°C (75–81°F), with pH 6.0–7.5 and soft to moderately hard water (5–15 dGH). They adapt to a fair range of conditions but dislike sudden swings. Weekly partial water changes keep nitrate low.
Best tank mates for upside-down catfish
These popular species share upside-down catfish' water needs and temperament. See the full list of 81 good matches.
Betta fish
6.5 cm (2.6 in) · 24–28°C (75–82°F)
Nerite snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Guppy
5 cm (2 in) · 22–27°C (72–81°F)
Dwarf gourami
7.5 cm (3 in) · 24–28°C (75–82°F)
Bristlenose pleco
12 cm (4.7 in) · 22–26°C (72–79°F)
Bronze corydoras
7 cm (2.8 in) · 21–26°C (70–79°F)
Angelfish
15 cm (5.9 in) · 24–29°C (75–84°F)
Assassin snail
2.5 cm (1 in) · 22–27°C (72–81°F)
Avoid keeping upside-down catfish with
- Cherry shrimp: Upside-down catfish eats small shrimp like cherry shrimp.
- Common goldfish: They need different temperatures: Upside-down catfish 24–27°C (75–81°F), common goldfish 15–22°C (59–72°F).
- Fancy goldfish: They need different temperatures: Upside-down catfish 24–27°C (75–81°F), fancy goldfish 18–23°C (64–73°F).
- Oscar: Oscar can eat upside-down catfish: they're small enough to fit in its mouth once it's grown.
- Celestial pearl danio: Upside-down catfish can eat celestial pearl danios: they're small enough to fit in its mouth once it's grown.
- Chili rasbora: Upside-down catfish can eat chili rasboras: they're small enough to fit in its mouth once it's grown.
Feeding
They are omnivores that eat almost anything. Use sinking pellets or wafers as the base, plus frozen bloodworms, brine shrimp and daphnia. Blanched peas or cucumber add plant matter. They often feed belly-up at the surface and are most active at dusk.
Behavior
This is one of the gentlest Synodontis, but it forages at night and can swallow very small fish such as chili rasboras, ember tetras and fry. Choose peaceful tankmates over about 1.25 inches (3 cm), such as African tetras, dwarf cichlids and medium-sized tetras, barbs and rasboras. A group rests together under wood or in caves. Avoid aggressive cichlids, and don't add dwarf shrimp.
Breeding
Home spawning is rare. A large, slightly cooler water change can trigger it, and pairs use caves or a pit in the substrate. Fry swim the right way up at first and start flipping over at around 7–8 weeks. Males are slimmer and darker than females.
Tips from experienced keepers
- Swimming upside down is normal for this species. Fry swim upright and flip as they grow.
- Keep at least four. A single fish tends to hide all day.
- Give them overhangs like driftwood or broad leaves to rest under, belly to the ceiling.
- Move them with a container instead of a net. Their fin spines snag easily in netting.
- Don't keep them with dwarf shrimp. They forage at night and eat small crustaceans.
Frequently asked questions
Why does my upside-down catfish swim upside down?
It's normal. This species feeds from the undersides of leaves, wood and the water surface while belly-up. Young fry swim upright and only start flipping over at around two months old.
How many upside-down catfish should be kept together?
Keep at least four. They live in groups in the wild and are bolder and easier to see when kept with their own kind.
How big do upside-down catfish get?
Usually about 3.5–4 inches (9–10 cm). They are one of the smaller Synodontis, so a 29-gallon (110 L) tank works for a small group.
Sources
We checked these references when writing this page. Values are for healthy long-term keeping, not survival limits. Last reviewed 2026-10-13. See our editorial policy.