Sharphead perch

Where they come from

Sharphead perch (Lepidoperca magna) are deep-reef sea perches from the temperate South Pacific, most often reported around southern Australia and New Zealand. They hang around steep rocky structure well below typical diving depths, which is why you almost never see them in shops. Cool water, dim light, and lots of oxygen is their world.

Tank setup

Plan big and cold. Mine settled in a 700 L system with a chiller and stayed rock-solid once I stopped trying to treat it like a tropical bass. Think quiet, shadowy ledges and high oxygen.

• Volume: 500 L minimum for a subadult, 700-1000 L for an adult. They are stocky, turn slowly, and appreciate footprint over height.
• Temperature: 12-16 C long term. They tolerate up to ~18 C briefly, but activity and appetite are better on the cooler side.
• Salinity: 1.024-1.026. Keep it steady. pH 8.0-8.3.
• Flow: Strong, well-oxygenated flow with some calmer pockets. Point one or two nozzles across the front to create a gentle gyre.
• Lighting: Dim. Think dawn/dusk. I ran a short photoperiod with shaded overhangs. Bright reef lights make them skittish.
• Aquascape: Big caves, vertical faces, and shaded ledges. They like to back into a cave and watch. Leave open sand or low rock in front for feeding.
• Filtration: Oversized skimmer, big bio capacity, and a chiller you trust. These fish are messy eaters. UV helps keep the water polished.
• Lid: Tight-fitting covers. They lunge at food and can hit the surface hard.

What to feed them

They are carnivores that key on movement. Expect to start with live or very tempting foods, then wean to thawed.

• Starter foods: Live gut-loaded ghost shrimp, small live marine crabs, or livebearers acclimated to salt (temporary only). Use sparingly as a bridge.
• Staples once weaned: Thawed marine-origin foods like prawns, squid strips, silversides, lancefish, and chunks of marine fish fillet.
• Technique: Use long tongs and wiggle the piece in front of the cave. Feed at dusk or under very dim light at first.
• Frequency: Juveniles every other day; adults 2-3 times per week. Better to offer a few solid bites than to stuff them.
• Supplements: Rotate items and soak a couple meals per week in a HUFA/vitamin product. Avoid relying on thiaminase-heavy fish (e.g., only silversides) long term.

How they behave and who they get along with

Sharphead perch are deliberate, cave-hovering ambush predators. Mine was shy for two weeks, then turned into a very predictable dusk-time hunter. Not aggressive without reason, but they will eat anything bite-sized.

• Good tankmates: Other coolwater, similarly sized, non-nippy fishes that do not blitz all the food (larger scorpionfish, coldwater hawkfish, gentle temperate wrasses).
• Questionable: Assertive groupers, triggerfish, large puffers. They outcompete or harass.
• No-go: Small fish, shrimp, and crabs. They are food.
• Social: Best kept singly. More than one will likely posture and stress unless you have a very large system and they can ignore each other.

Breeding tips

Realistically, there are no hobbyist breeding reports for Lepidoperca magna. Like many serranids, they likely form pairs or small groups and broadcast spawn in deep, cool water with seasonal cues. You would need a large, chilled, dimly lit system and simulated seasonal changes to even explore pairing. For now, enjoy them as a display fish and put your energy into stable conditions and a strong feeding routine.

Common problems to watch for

• Barotrauma in new arrivals: Wild-caught deep fish can arrive with bulging eyes, buoyancy problems, or a protruding stomach. If you see this at the shop, pass. Recovery is hit-or-miss.
• Refusing food: Very common the first week. Dim the lights, offer smaller moving pieces, and try at dusk. Live ghost shrimp can kick-start interest.
• Overheating: Anything above ~18 C for long stretches leads to heavy breathing and loss of appetite.
• Low oxygen: They perk up with strong aeration. Keep surface agitation high and clean the skimmer cup often.
• Parasites: Flukes and worms are not rare. A proper, chilled quarantine with praziquantel has saved me headaches.
• Injury from feeding strikes: They hit hard. Use tongs and give them room so they do not face-plant into rock.
• Nutritional issues: Monotonous diets (only silversides) can cause weight loss over time. Rotate foods and add vitamins.