Pacific rock sole
Lepidopsetta bilineata
The Pacific rock sole features a flattened body, dark brown to olive coloration, and distinct lateral lines with light and dark mottling.
This page includes AI-generated images. Why am I seeing AI images?
About the Pacific rock sole
This is a cold-water right-eyed flatfish from the North Pacific that lives on sand-and-gravel bottoms and tops out around 2 feet. It is a bottom-hugging predator that munches worms, crustaceans, and other benthic critters, and it is really more of a public-aquarium/sea pen kind of animal than a home-tank fish.
Also known as
Quick Facts
Size
60 cm
Temperament
Peaceful
Difficulty
Expert
Min Tank Size
300 gallons
Lifespan
up to 26 years
Origin
North Pacific (eastern Pacific: Baja California to the Aleutian Islands and southeastern Bering Sea)
Diet
Carnivore - benthic invertebrates (mollusks, polychaete worms, crustaceans), brittle stars, and fishes
Water Parameters
1.5-10.1°C
7.8-8.4
8-12 dGH
Need a heater for this species?
This species needs 1.5-10.1°C in a 300 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give it a big, wide footprint and a deep sand bed (fine sand, 2-4 inches) - they want to bury and scoot, and sharp crushed coral will wreck their belly and fins.
- Run this fish cold: shoot for 45-55F with a chiller, salinity 1.023-1.026, pH around 8.0-8.3, and keep ammonia/nitrite at zero because flatfish go downhill fast when water gets dirty.
- Low-to-moderate flow with lots of oxygen works best; they hate getting blasted off the bottom, but they do poorly in stale water so aim powerheads across the surface and use a strong skimmer.
- Feed meaty marine foods on the sand: chopped shrimp, clam, squid, and silversides, plus frozen mysis; use feeding tongs and target-feed after lights dim so tankmates do not steal everything.
- Avoid fast, aggressive feeders and nippy fish (wrasses that pick, triggers, large hawkfish) - they will stress it out and outcompete it; calm coldwater species that ignore the bottom are safer.
- Watch for mouth and gill irritation from sand and for bacterial sores on the underside; if you see red patches or fuzz, fix substrate and water quality first, then treat in a hospital tank.
- Do not mix with small fish or crustaceans you care about - once it settles in, anything that fits in its mouth can disappear overnight.
- Breeding in home tanks is basically a unicorn: they are seasonal coldwater spawners and you would need big temperature and light cycling plus room for pelagic eggs and larvae.
Compatibility
Good Tankmates
- Other peaceful coldwater flatfish or small, non-bully bottom types (think small soles/flounders). They mostly just want sand and personal space, so as long as nobody is trying to sit on the same patch of bottom, its fine.
- Sculpins and other chill coldwater ambush fish that are not huge (buffalo sculpin-type vibes). They tend to mind their own business and dont usually harass a buried sole, just watch the size difference.
- Greenlings (like kelp greenling) in a roomy coldwater setup. They cruise midwater/structure and generally leave a rock sole alone if everyone is well fed.
- Small to medium rockfish species that are on the calmer side (juveniles or smaller species). They hang up in the water column and dont usually pick on a sole, just avoid anything that gets big enough to eat it.
- Pipefish (coldwater species) if your system is mature and you can feed carefully. They are mellow and not competitive, and the sole is a non-issue temperament-wise.
- Non-aggressive inverts like larger snails and cleaner-type shrimp. A rock sole is usually more interested in worms, pods, and meaty bits than in messing with tank janitors.
Avoid
- Big predatory rockfish or lingcod-type predators. If it can fit the sole in its mouth, it will eventually try, and a buried fish is an easy target at lights-out.
- Aggressive, nippy fish like larger wrasses or anything that likes to peck at fins and eyes. They will hassle a flatfish that just wants to sit and hide in the sand.
- Crabs and other grabby crustaceans (especially larger shore crabs). They will pinch at a resting sole, steal food, and generally turn the bottom into a stress zone.
Where they come from
Pacific rock sole are cold-water flatfish from the North Pacific - Alaska down through the Pacific Northwest. They live on sandy or muddy bottoms, half-buried most of the day, waiting for food to wander by. If you have ever snorkeled or trawled videos in those areas, you have seen the vibe: cold, dim, lots of current, and the bottom is everything.
This is not a "marine fish" in the tropical reef sense. Think cold-water marine system (50-60F / 10-16C range), heavy filtration, and a bottom-focused setup.
Setting up their tank
Tank size is where most attempts fall apart. These fish get bigger than people expect and they need floor space more than height. A long, wide tank beats a tall one every time. I would not bother under 180 gallons, and bigger is honestly nicer because you can give them a real sand flat to settle into.
- Tank footprint: prioritize length and width (a 6-8 foot tank is your friend)
- Substrate: fine sand, deep enough for them to bury (2-3 inches works well)
- Rockwork: keep it minimal and stable; put heavy rocks on the glass, then sand around them
- Flow: moderate, but avoid blasting the sandbed into dunes
- Lighting: they do not need it bright; lower light keeps them calmer
Keep the water cold and stable. That usually means a chiller, and you want it sized with headroom because pumps and room temps add heat fast. I ran mine with a big sump, oversized skimmer, and a lot of mechanical filtration because sand-sitters make a mess and you will be feeding meaty foods.
Do not put them in a tropical marine tank "just to try." Warm water and high temps from reef gear will shorten their lifespan fast, and they go downhill in a way that looks like mystery disease.
Cover matters. Flatfish can and will launch if startled, especially new arrivals. A tight lid also keeps humidity from wrecking lights when you are running a cold system in a warm room (condensation is real).
What to feed them
These are ambush predators that eat bottom critters and small fish in the wild. In a tank, you want a varied, meaty diet and you want it delivered to the bottom so they actually find it. Once settled, they usually learn the routine and will come "alive" at feeding time, even during the day.
- Staples: thawed mysis, chopped shrimp, chopped clam, squid, krill (not as the only food)
- Great additions: pieces of marine fish (like smelt) in moderation, roe/eggs occasionally
- If they are stubborn: live ghost shrimp or small live marine shrimp to kickstart feeding
- Vitamins: soak foods sometimes, especially if you rely on frozen mixes
Target feeding helps a lot. I use long tongs or a feeding stick and place food right in front of their face on the sand. If you just broadcast food in a big tank, the crabs, shrimp, and faster fish will clean it up while the sole sits there like nothing happened.
Feed smaller portions more often at first (even daily) until you see a nice, rounded body. Once they are established, 3-5 solid meals per week is usually fine, depending on temp and tankmates.
How they behave and who they get along with
Pacific rock sole are generally chill. They spend a lot of time buried with just the eyes showing, then they do a quick burst to grab food. The main "aggression" you will see is feeding competition. They are not out patrolling like a wrasse, but they will absolutely inhale anything small enough to fit in their mouth.
- Good tankmates: cold-water, non-bullying fish that do not pick at the bottom (some sculpins, larger gobies, certain temperate rockfish with caution)
- Avoid: fin-nippers and bottom pickers that will harass them (some triggers, large aggressive crabs)
- Also avoid: tiny fish and shrimp you want to keep - they may become food
- Inverts: tougher snails can work; small decorative shrimp are a gamble
They can live with other flatfish if the tank is big and the feeding is managed, but crowding the bottom is asking for stress. Give each fish its own "patch" of sand and multiple feeding spots so one does not get bullied off meals.
Watch for tankmates that steal food. A sole that misses meals will look fine for a while, then one day you realize it is pinched behind the head and losing condition.
Breeding tips
Breeding at home is basically a moonshot. They are seasonal spawners in the wild and their larvae are planktonic before they settle and "turn" into the flatfish shape. That means you would need temp cycling, likely changes in day length, a mature pair (hard to sex), and then a serious live food pipeline for tiny marine larvae.
If you ever get eggs, treat it like a marine larval project: separate rearing tank, gentle aeration, pristine water, and live foods on deck (rotifers, then copepods/Artemia). Most hobbyists stop at "cool, they spawned" because raising them is the hard part.
Common problems to watch for
Most issues with rock sole are husbandry and environment, not some exotic pathogen. If something looks off, I always check temperature stability and feeding success first.
- Heat stress: lethargy, poor appetite, rapid decline in warm water
- Skin damage: scrapes from sharp gravel or unstable rocks; they are built for sand, not crushed coral
- Starvation by competition: they are slow feeders compared to most fish
- Parasites from wild-caught specimens: flukes and external parasites can show up after the "settling in" period
- Bacterial infections after abrasions: red patches, cloudy areas, frayed fins
Sharp substrate is a silent killer for flatfish. If you would not want to belly-slide on it, your sole does not either. Fine sand saves you a lot of headaches.
Quarantine is worth the effort with this species, but make it flatfish-friendly: fine sand in a tray or a removable container, dim lighting, and lots of oxygen. Bare-bottom QT can work short term, but stressed soles will scrape themselves and then you are treating wounds on top of everything else.
If your sole is "always buried" and never comes out to feed, do a nighttime check with a dim room light. Some individuals stay nocturnal for a long time, and you may need to feed after lights out until it learns your schedule.
Similar Species
Other marine peaceful species you might be interested in.
Abe's eelpout
Japonolycodes abei
Japonolycodes abei is a temperate, deepwater demersal eelpout (family Zoarcidae) endemic to Japan (Kumano-nada Sea reported; other sources also report Sagami Bay and Tosa Bay). It is the only species in the genus Japonolycodes and occurs roughly 40-300 m depth, making it an uncommon/atypical aquarium species.
Banggai Cardinalfish
Pterapogon kauderni
Banggai cardinals just sort of hover like little underwater satellites, and the bold black bars with those long, polka-dotted fins look unreal under reef lighting. They're super chill most of the time, but once a pair forms you'll see real "fish drama," and the male will even mouthbrood the babies like a champ.
Ben-Tuvia's goby
Didogobius bentuvii
This is a tiny little Mediterranean goby from the Israeli coast that lives down on the bottom over muddy-sand, and it is likely a burrower. In other words, it is a blink-and-you-miss-it kind of fish - super small, demersal, and more about sneaky bottom-dweller vibes than flashy swimming.
Bigeye brotula
Glyptophidium longipes
Glyptophidium longipes is a deepwater cusk-eel (brotula) from the western Indian Ocean - a slender, eel-ish fish with oversized eyes and long ventral-fin rays. It is a bathyal slope species from a few hundred meters down, so its real-world needs (cold, dark, high-pressure habitat) make it essentially an observation-only "research" animal rather than a practical aquarium fish.
Bigeye clingfish
Kopua nuimata
Kopua nuimata is a tiny deepwater clingfish with big eyes and a neat pink-and-orange banded pattern. It lives way down on reefy slopes (roughly 160-337 m), so its "care" is mostly academic - its natural habitat is cold, dark, high-pressure water that we just do not replicate in home aquariums.
Black dwarfgoby
Eviota vader
Eviota vader is a truly tiny, purplish-black little reef goby from Papua New Guinea that was only described in 2025. It was named after Darth Vader because the whole fish is basically dark purple-black, which is wild for an Eviota. Its size is the big story here - at barely over 1 cm, its main challenge in aquariums would be making sure it actually gets enough to eat.
More to Explore
Discover more marine species.
African conger (Japonoconger africanus)
Japonoconger africanus
This is a smallish deep-water conger eel from the eastern Atlantic (Gabon down to the Congo), and it lives way deeper than anything we normally keep at home. It is a predator that eats fish and crustaceans, and while it is a cool species on paper, it is basically not an aquarium fish in any normal sense due to its deep-water habitat and lack of established captive care info.
Arabian spiny eel
Notacanthus indicus
Notacanthus indicus is a deep-sea spiny eel (family Notacanthidae; not a true eel) known from the Arabian Sea on the continental slope at roughly ~960–1,046 m depth, with reported maximum length around 20 cm TL; it is a deep-water bycatch species and not established in the aquarium trade.
Atlantic pomfret
Brama brama
Brama brama is the Atlantic pomfret (aka Ray's bream) - a deep-bodied, open-ocean pelagic fish that cruises around in small schools and follows water temps. It is a legit big, wild marine species (not an aquarium fish) that eats other small sea critters like fish and squid, and it ranges across a huge chunk of the Atlantic plus parts of the Indian and South Pacific.
Australian sawtail catshark
Figaro boardmani
Figaro boardmani is a small, deepwater Australian catshark with these cool saw-like ridges of spiny denticles along the tail and a neat pattern of dark saddle bands. It lives way down on the outer continental shelf and slope, so its natural water is cold, dim, and stable - totally not a typical home-aquarium fish. Diet-wise its a predator that goes after fish, crustaceans, and cephalopods.
Banded stargazer
Kathetostoma binigrasella
This is a New Zealand stargazer that lives half-buried in sand or mud with its eyes pointed up, waiting to rocket upward and nail passing prey. It has those neat dark saddle-bands across the back (especially as a juvenile), and like other stargazers it is venomous with spines near the gill cover/pectoral area - definitely a look-dont-touch fish.
Barlip reef-eel
Uropterygius kamar
Uropterygius kamar is a smaller moray (a reef-eel) that spends its time tucked into rockwork and coral rubble, poking its head out when it smells food. FishBase notes it comes in two color morphs and lives on reef-associated rubble areas, so in a tank it really appreciates lots of tight caves and crevices. Like most morays its whole vibe is secretive ambush predator, not open-water swimmer.
Looking for other species?