Whale catfish
Rita rita
The Whale catfish features a robust body, long barbels, and dark brown to olive-green coloration with lighter spots.
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About the Whale catfish
Rita rita is a big, predatory river catfish from South Asia that spends most of its time cruising the bottom and waiting to ambush food. Juveniles can look kind of "cute and manageable" in the shop, but this fish is basically a tank-buster that will eventually want serious space and will absolutely snack on anything it can fit in its mouth.
Also known as
Quick Facts
Size
150 cm
Temperament
Semi-aggressive
Difficulty
Expert
Min Tank Size
300 gallons
Lifespan
10-15 years
Origin
South Asia
Diet
Carnivore - insects, mollusks, shrimp, and fish; in aquaria use meaty pellets plus frozen/raw seafood pieces
Water Parameters
18-26°C
6.5-8
0-30 dGH
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This species needs 18-26°C in a 300 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Plan for a monster: an adult Rita rita needs a big footprint tank (think 8 ft long, 300+ gallons) with heavy filtration and a tight lid - they can bulldoze decor and shove lids around.
- Use sand or smooth fine gravel and keep the layout simple with big driftwood and stout caves; skip sharp rock because they love to wedge themselves in and will shred barbels and belly skin.
- They do best in warm, oxygen-rich freshwater: roughly 75-82 F, pH around 6.5-7.8, and low ammonia/nitrite at all times; they react fast to dirty water with frayed fins and barbel erosion.
- Feed after lights-out and use tongs so you do not donate fingers - they hit like a vacuum; rotate chunky foods like shrimp, mussel, fish fillet, earthworms, and quality sinking carnivore pellets.
- Do not keep with anything they can fit in their mouth, which is a lot; tankmates have to be big, tough, and not skittish (large barbs, big cichlids, other robust catfish), and even then expect occasional bullying.
- They are strong diggers and will uproot plants and toss stones, so anchor wood/rocks directly on the tank bottom and protect heaters/intakes with guards.
- Watch for bloat and fatty-liver issues if you overdo oily fish or feed huge meals - smaller, regular feeds keep them moving and pooping normally; also keep an eye on torn barbels from rough substrate or cramped hides.
- Breeding at home is basically a unicorn: most reports involve seasonal river cues and huge spaces, so do not buy one expecting fry unless you are set up like a public aquarium.
Compatibility
Good Tankmates
- Big, tough carps like larger barbs (tinfoil barbs, big filament barbs) - fast, not easily bullied, and not small enough to get inhaled at night
- Medium-large cichlids that are not total psychos (severums, chocolate cichlids, larger acaras) - they can hold their own, and they stay up in the water column more than the Rita does
- Decent-sized schooling fish like silver dollars - quick, stay midwater, and they are usually too wide-bodied to be seen as food once everyone is grown
- Other heavyweight river fish like snakeheads and giant gourami sized tankmates (only if the tank is huge) - basically anything that matches the 'big, boisterous, not snack-sized' vibe
- Larger knifefish or spiny eels (grown, not baby) - they tend to mind their own business, but give lots of hides so the whale catfish is not constantly defending one cave
- Big plecos (common/sailfin types) - usually fine as long as you have multiple caves and you feed heavy after lights-out so the catfish is not competing all night
Avoid
- Small community fish like tetras, danios, guppies, and most rasboras - they look like food, and this catfish is a night hunter that will absolutely test that theory
- Slow fish with fancy fins (angelfish, fancy goldfish, long-fin gouramis) - they get stressed or shredded, and they cannot dodge the late-night ambush stuff
- Other bottom predators or hyper-territorial catfish (redtail catfish, big Pimelodus, large synodontis in tight quarters) - too much cave drama, fin damage, and constant pushing matches
- Anything super aggressive that wants to own the whole tank (some big Central American cichlids, especially if they are breeding) - you end up with nonstop fights around the bottom
Where they come from
Rita rita is a big river catfish from South Asia - think the Ganges and related river systems in India, Bangladesh, Nepal, and Pakistan. They live in murky, fast-moving water with shifting sand and silt, lots of seasonal change, and plenty of food washing by. That background explains most of their quirks in the aquarium: messy eater, strong, and not shy about swallowing tankmates.
Setting up their tank
This is an expert fish mostly because of size, strength, waste, and temperament. A cute juvenile turns into a serious, heavy-bodied predator. If you cannot provide a very large footprint and industrial-level filtration, you will be fighting problems nonstop.
Do not buy one for a "grow out" tank unless you already have the final tank ready or scheduled. They outgrow typical home setups fast, and rehoming a huge predatory catfish is harder than it sounds.
Tank size: go bigger than you think, and prioritize floor space over height. An adult needs room to turn without scraping itself and enough territory to settle without constantly pacing.
- Footprint is king - long and wide beats tall.
- Heavy lid - they can surge and bump covers when startled.
- External canisters or sump with big mechanical stages (socks/floss) because they produce a lot of solids.
- High turnover with flow breaks - strong circulation, but give them calmer pockets to rest.
- Heater with guard, and protect intakes with sturdy screens. They can wedge themselves into bad spots.
Substrate and decor: I have the best luck with sand or very smooth fine gravel. Sharp gravel + a big catfish that bulldozes around is a recipe for torn barbels and belly scrapes. Use big driftwood, rounded rocks, and large, stable caves. Everything has to be "catfish-proof" - if you can move it with one hand, the fish will eventually move it with its face.
Silicone down or brace decor so it cannot topple. I use heavier stones as "stops" to keep driftwood from shifting when the fish wedges under it.
Water: they handle a range, but they do better with stable, clean water and lots of oxygen. Plan for big, frequent water changes. If nitrates climb, they tend to get listless and you start seeing fin edges and barbel wear go downhill.
What to feed them
They are opportunistic predators and scavengers. In a tank, they will learn to eat almost anything meaty, but the goal is a varied diet that does not turn them into a greasy, fatty mess. Overfeeding is the fastest way to ruin water quality and the fish at the same time.
- Staples: quality sinking carnivore pellets and large catfish sticks.
- Rotate in: shrimp, mussel, clam, squid, white fish fillet, earthworms.
- Occasional: live or frozen foods like prawns or large insects if you can source clean ones.
- Skip feeder fish - parasite risk, and it encourages "everything is food" behavior even more.
Go easy on fatty meats (like a steady diet of beef heart) and super oily fish. They will eat it, but long term it is not kind to their organs or your water.
Feeding rhythm: adults do well with larger meals a few times a week instead of daily stuffing. I like feeding after lights dim. Use tongs or a feeding stick so you can place food where it will be eaten, not blasted into a filter intake. Pull leftovers after 10-15 minutes - they can hide a surprising amount of rot under wood.
How they behave and who they get along with
Rita rita is bold in a blunt, catfish way. They spend a lot of time parked under cover, then suddenly go into "vacuum cleaner with jaws" mode when food hits the water. They are not a community fish. The rule is simple: if it fits in the mouth, it is food, and they can fit more than you expect.
- Best tankmates are big, tough fish that are too large to swallow and not fin-nippy.
- Avoid slow, delicate fish and anything eel-shaped that invites grabbing.
- Avoid small catfish and plecos unless you want injuries - plecos can rasp slime coats and start wars at night.
- Expect some territorial behavior, especially in tighter tanks.
Nighttime changes everything. A tank that looks peaceful all day can become a hunting ground after lights out. If you are testing tankmates, observe after dark with a dim room light.
They startle easily if the tank is bare and bright. Give them cover and shaded zones, and they calm down a lot. Also, they are strong diggers. If you have plants, assume they will be uprooted unless they are tied to wood or in protected pots.
Breeding tips
Breeding Rita rita in home aquariums is rare. In the wild, they cue off seasonal floods, temperature shifts, and big changes in flow and food availability. Most hobbyists keep single specimens or mixed predators where spawning is not even on the table.
If you want to explore breeding, think "river season simulation": a cool, lower-water period with leaner feeding, then a gradual warm-up, heavier feeding, and big water changes with stronger flow like a flood pulse. Even then, you need a massive setup and likely a compatible pair, which is its own challenge.
Common problems to watch for
Most issues with this species come from three things: injuries from decor, dirty water from heavy feeding, and bad tankmate choices.
- Barbel wear and mouth damage: usually sharp substrate, rough rock, or constantly rooting in dirty mulm.
- Cloudy water and chronic nitrate: too much food, not enough mechanical filtration, or infrequent water changes.
- Bloat/constipation: big meals of rich food, not enough variety, or gulping substrate with food.
- Scrapes and fungus patches: from squeezing into tight caves or shifting decor; they heal fast if water is clean.
- Ich and other parasites: often introduced with feeders or poorly quarantined live foods.
If you see red patches, frayed barbels, or the fish starts "breathing heavy" at the surface, treat it like a water-quality emergency first. Test, do a big water change, clean mechanical media, and increase aeration before you start throwing meds in.
One last practical thing: plan your maintenance around them. Big siphon, big buckets or a hose to a drain, and a way to move decor safely. This is not a fish you want to net often. I do any major tank work with lights off and a clear plan so the fish does not slam into glass.
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