Jordan's cod

Where they come from

Jordan's cod (Gadella jordani) is a deep-slope codling from the western and central Pacific. Think muddy and silty continental slopes a few hundred meters down, way below reef life and sunlight. They cruise the bottom edges in cold, dark water picking off small fishes and crustaceans.

Setting up their tank

This is a cold, dim, very stable system. If you cannot chill the water and keep oxygen high, do not buy one. They are deepwater fish and react badly to bright light, warm temps, and swings.

• Tank size: aim for 300+ gallons (1100+ L) with at least a 6 ft length. They get big and like to cruise.
• Temperature: 8-12 C (46-54 F), steady. A serious chiller, insulated plumbing, and a temperature controller with an alarm are your friends.
• Salinity: 35 ppt (1.025-1.026). pH 7.9-8.2. Keep it boringly stable.
• Oxygen: heavy aeration and surface agitation. Low temps help, but you still want strong gas exchange.
• Lighting: very dim. Think dusk. Short photoperiod. Black background and sides help them relax.
• Aquascape: open sand or bare bottom with big, stable caves and arches. I like a couple of large PVC culverts hidden with rock so they can retreat.
• Flow: moderate laminar flow along the front for cruising, with some dead calm pockets behind rock.
• Lid: tight-fitting. They are strong, nervous, and can bolt upward if startled.
• Filtration: oversized skimmer and lots of bio media. At cold temps, bacteria work slower, so give them surface area.

What to feed them

They are carnivores that prefer moving prey. New arrivals often ignore everything unless it wiggles. Expect to start with live and then wean.

• Starter foods: live salt-tolerant shrimp, live marine baitfish if you have a clean source. Offer at lights-down.
• Transition: use a feeding stick to make thawed items move. Silversides, lancefish, squid strips, prawn pieces, and marine mysis all work.
• Routine: 3-5 small feeds per week once settled. They do better on several modest meals than big dumps.
• Supplements: soak some meals in a marine vitamin/HUFA mix. Rotate items to avoid thiaminase-heavy diets dominating.
• Avoid: freshwater feeders (goldfish, rosy reds), oily fish every day, and anything you cannot vouch for health-wise.

How they behave and who they get along with

Calm, crepuscular, and surprisingly quick in short bursts. They spend a lot of time hovering just off the bottom or tucked into a cave mouth. Once settled, they do a slow patrol along the front of the tank at dusk.

• Temperament: not aggressive to similar-sized fish, but anything bite-sized is food.
• Tankmates: best kept solo. If you must mix, stick to other chilled-water, non-belligerent species of comparable size that ignore food presented on a stick. Boisterous reef fish stress them out.
• Territory: give multiple retreats so they do not feel cornered. Sudden movement in bright light can trigger panicked dashes.

Breeding tips

Realistically not happening at home. They are deepwater spawners with pelagic eggs and larvae. No captive reports I trust. Focus on stable long-term holding rather than pairing.

Common problems to watch for

• Decompression injuries from collection: positive buoyancy, bulging eyes, or floating tail-up. Sometimes they arrive like this.
• Refusal to feed: very common early on, especially in bright tanks or warm water.
• Temperature drift: a few degrees up can push them off food and lower oxygen.
• Ammonia spikes: heavy meaty feeding plus slow coldwater biofiltration can catch you off guard.
• Internal parasites: wild deepwater fish often carry worms. Weight loss despite eating is a hint.
• Abrasion and snout damage: they bolt and scrape on rock if startled by lights or sudden shadows.

Acclimation goes slow and cold. Keep the bag and bucket shaded, match temperature first with the chiller running, and drip over 45-60 minutes. Move the fish with a soft cradle or container, not a net, and get the room quiet for the first few days.