Footballfish

Where they come from

Footballfish (Himantolophus danae) are deep-sea anglerfish from the open ocean, usually 400-2000 m down. Think near-freezing water, high pressure, and total darkness. Females are the big, round ones with the glowing lure. Males are tiny and mostly live attached to females in the wild.

Setting up their tank

You are basically building a tiny deep sea. Cold, dark, quiet, and very stable. Pressure replication is out of reach for hobby gear, so you work with the narrow window of animals that arrive able to tolerate surface pressure (rare) and then reduce every other stressor to near-zero.

• Temperature: 2-6 C. Use an oversized chiller and insulate the tank and lines. Alarms and backup power are a must.
• Salinity: 34-35 ppt. pH 7.9-8.2. Keep parameters rock-steady on a mature system.
• Lighting: darkness. Observe with dim red light only. No camera flashes.
• Shape and flow: round or rounded-corner tank with gentle circular flow so the fish can hover midwater without rubbing. Cover intakes with soft mesh.
• Filtration: large skimmer, big biofilter, and UV to keep bacterial loads low at cold temps. Put the skimmer/UV in the sump to keep the display calm.
• Oxygen: high O2, but avoid visible bubbles in the display to prevent abrasion. Gas exchange and oxygenation in the sump is safer.
• Interior: bare tank. No rocks, no sharp fittings. Blacked-out sides help them settle.
• Handling: always move the fish submerged. Use soft, knotless cradles. Avoid touching the lure (esca) and skin.

What to feed them

They are ambush predators. The trick is to present food so it looks like prey approaching the lure. You are better off with small, high-quality marine foods and patience than giant items they might regurgitate later.

• Offer: silversides, capelin, small herring pieces, squid strips, krill, and shrimp. Rinse well after thawing.
• Use a feeding wand or long tweezers. Wiggle the piece near the lure and then past the mouth. Give them time to strike.
• Feed sparingly: 1 modest item every 3-7 days. Overfeeding leads to regurgitation and infections.
• Rotate foods and add a marine vitamin soak now and then to dodge thiaminase issues from smelt/silversides-heavy diets.
• If the fish refuses food for several days, do not chase it with food. Reduce disturbance, try again at night with red light.

How they behave and who they get along with

They mostly hover motionless, then snap open that huge mouth for a quick strike. Sudden light or vibration makes them flinch and bump the walls, so keep the room calm.

• Tankmates: none. Anything that moves may get eaten or will panic them.
• One per system: females are solitary. Males are vanishingly rare in collections and not suitable as tankmates anyway.
• Activity: nocturnal. Do feeding and maintenance at night under red light if possible.

Breeding tips

Realistically, no. In nature, tiny males fuse to females and become permanent mates. Capturing a compatible pair alive and getting them to that point in a tank has not been done in the hobby, and public aquaria have not reported success either. Focus on short-term stabilization rather than long-term pairing.

Common problems to watch for

• Feeding refusal: very common. Cut disturbance, switch to smaller prey, try at night with a subtle wiggle near the lure.
• Regurgitation hours after eating: feed smaller portions and extend the interval. Check temperature stability.
• Skin abrasions and lure damage: usually from bumping walls or rough handling. Round the tank, slow the flow, and keep it dark.
• Bacterial blooms and slime: cold water slows biofiltration. Use robust UV and a mature filter. Discuss antibiotics with a vet if lesions appear.
• Light shock: any bright light can cause frantic swimming. Black out the tank and use dim red only.
• Sudden decline after capture: many arrive with internal injuries or decompression stress you cannot fix. Humane euthanasia may be the kindest outcome in some cases.