Okhotsk Hookear Sculpin

Where they come from

Okhotsk Hookear Sculpins are a coldwater, bottom-hugging sculpin from the North Pacific. Think Sea of Okhotsk, the Bering Sea, and chilly waters off northern Japan and the Russian Far East. They live on sand and rubble on the continental shelf, picking off little crustaceans and worms while pretending to be a rock.

Setting up their tank

They spend most of their time perched and watching the world go by. Give them floor space, stable rockwork, and dark nooks. Mine always chose the quiet, shaded side of the tank with a steady bit of flow and high oxygen.

• Tank size: 40 gallons is the smallest I would do for one. More floor space is better. For two, think 55-75 gallons.
• Temperature: 2-8 C (36-46 F) long term. Brief flirt with 10 C (50 F) is usually fine, but keep it cold and steady.
• Salinity: 33-35 ppt (SG 1.024-1.027).
• Substrate: Fine sand with a shallow tray or pocket of muddy sand if you can manage it. They like to settle in softer spots.
• Rockwork: Solid caves and overhangs. Stack rocks on the glass, not on sand, so nothing shifts when they wiggle underneath.
• Flow and oxygen: Moderate flow with some calm pockets. Lots of aeration. A strong skimmer helps with both oxygen and waste.
• Filtration: Heavy biofiltration and frequent mechanical cleaning. Protein-rich diets add up fast in a cold tank.
• Lighting: Dim to moderate. They do not love bright reef lights.
• Lid: Tight cover. They can surge up when startled.
• Chiller sizing: Get a chiller that can hold setpoint in summer with a margin. Insulate the return line so you are not cooling the room.

What to feed them

They are ambush predators with a slow, deliberate strike. Start with moving foods, then transition to frozen. Mine took frozen within a week after a few target-feeding sessions.

• Live or thawed mysis shrimp (a great starter food).
• Pieces of raw marine shrimp, krill, or clam.
• Small strips of silverside or sand lance (not too oily, and in moderation).
• Marine worms like ragworms or pieces of lugworm.
• Amphipods and shore shrimp from a clean, quarantine source.

Feeding schedule that worked for me: small meals 3-4 times per week. They do not need daily stuffing. I add a vitamin/omega soak to frozen food once a week.

How they behave and who they get along with

Mostly they sit, watch, and scoot a few inches at a time. They are not bullies, but they are very willing to eat anything that fits in their mouth. They will defend a favorite cave from another similar sculpin.

• Better bets: similar-sized coldwater, slow fish that do not compete hard for food. Think other small sculpins (with caution), small snailfishes, or a mellow prickleback that is not nippy.
• Usually safe: large snails and urchins. They ignore them.
• Usually not safe: shrimp, small crabs, tiny fish, and decorative inverts you care about. If it moves and is bite-sized, it is food.
• Avoid: large aggressive fish that will outcompete them, and fast pelagics that will eat all the food before it hits bottom.

Breeding tips

I have not seen confirmed home-breeding of Artediellus ochotensis. Most sculpins lay adhesive eggs in a crevice and the male guards them. Hatching and larval rearing are the tough parts, often needing chilled live plankton and very clean, stable flow.

• If you try, mimic seasons: several months at 2-4 C with short photoperiod, then a slow climb to 6-8 C and longer light.
• Offer several tight caves of different sizes. They like narrow entries.
• Keep only one pair per tank and watch for harassment. Have a divider ready.
• Prepare live feeds ahead of time (rotifers, copepods) in chilled culture if you ever get eggs.

Common problems to watch for

• Heat stress: above 10-12 C they breathe fast, stop eating, and go blotchy. Drop temp gradually and boost aeration.
• Low oxygen: power outages or pump failures hit coldwater fish hard. Battery air pump and surface agitation are your friends.
• Starvation in mixed tanks: they lose out to faster feeders. Target feed and slow the flow at meal time.
• Dirty substrate pockets: they sit in it, so trapped waste can cause skin issues. Vacuum lightly and keep flow moving across the bottom.
• Wild-caught hitchhikers: internal worms or crustacean parasites are not rare. Quarantine in a chilled setup.
• Overfeeding oily fish: leads to fatty deposits and messy water. Rotate foods and keep portions small.
• Injury from unstable rock: they wedge into cracks. Build rockwork sturdy and test for wiggle before filling.
• Mis-ID at purchase: different sculpins have different adult sizes and temp needs. Get a positive ID before you set equipment.