Demon Stingerfish

Where they come from

Demon stingerfish show up across the Indo-West Pacific on sandy and rubble bottoms, lagoon shallows, and seagrass edges. They bury themselves in light sand, then "walk" around on those weird finger-like pectoral rays at dusk to ambush anything careless enough to pass by.

Setting up their tank

Think of this fish like a land mine with fins. It wants a calm sand patch, dimmer light, and rock that will not crash down when it shuffles underneath. They top out around 7-8 inches, so give them floor space more than height.

• Tank size - 40 breeder is the bare minimum single fish footprint; 55+ gallons with a 36 x 18 in or larger footprint is better.
• Substrate - 2-3 inches of fine sand. Skip coarse crushed coral. They bury daily, and sharp substrate rubs the skin.
• Aquascape - Stable rock islands with open sand in front. Test stability by wiggling pieces before water goes in.
• Flow - Gentle to moderate, random. Avoid blasting the sand bed; they hate being uncovered by powerheads.
• Lighting - Low to moderate. Give shaded zones.
• Filtration - Strong protein skimmer and regular siphoning. Meaty foods foul water fast.
• Lid - Tight. They are not jumpy, but things that hunt at night sometimes end up where you do not expect.
• Parameters - 1.023-1.026 SG, 75-80 F (24-27 C), pH 8.1-8.4, stable alkalinity. Keep ammonia and nitrite at 0, nitrates preferably under 20 ppm.
• Tools - Long feeding tongs and a rigid container for moving them. Never use a net; spines snag.

Acclimate slowly with lights down. I drip for 45-60 minutes and transfer in a specimen container. Keep hands clear of the dorsal spines at all times.

What to feed them

Feeding is the make-or-break part. New arrivals often only recognize live prey. The goal is to wean them to thawed marine foods on tongs.

• Starter prey - Live saltwater ghost/grass shrimp work very well. Salt-converted mollies are an option. Avoid goldfish/rosies; they carry disease and their thiaminase content leads to long-term issues.
• Transition - Offer a live shrimp on tongs, then swap to a freshly thawed shrimp piece the next feed. Add a little wiggle and feed at dusk.
• Staples - Pieces of raw marine shrimp, squid, scallop, and marine fish flesh (e.g., snapper, pollock). Silversides only occasionally.
• Supplements - Soak foods in a vitamin/HUFA mix 1-2x per week.
• Frequency - Adults every 2-3 days; juveniles every other day. One solid, belly-filling piece per feeding. They put on fat easily.

How they behave and who they get along with

Most of the day they look like a lump of sand with eyes. At night they roam slowly, and when something edible wanders close they strike like a mousetrap. They can swallow fish nearly half their own length, so assume anything smaller is on the menu.

• Safest setup - Species-only or with another similarly sized, non-nippy scorpionfish in a roomy tank.
• Usually OK (case by case) - Larger, calm fish that ignore the bottom and do not outcompete at feeding time. You will still need to target feed the stingerfish.
• Avoid - Triggers, puffers, large wrasses, and dottybacks that nip fins. Also avoid crabs and shrimp; they are prey.
• Feeding competition - Fast tangs, angels, and wrasses will steal food. If you try them together, feed the speedsters first on the opposite side, then target feed the stingerfish.

Breeding tips

Not a home-aquarium project. Inimicus species are thought to broadcast spawn pelagic eggs in the wild, usually seasonally. There is no reliable way to sex them visually, pairing attempts are risky, and no documented captive breedings in hobby tanks that I am aware of. Focus on long-term single-fish care.

Common problems to watch for

• Refusing frozen food - The most common issue. Keep using live shrimp as a bridge and stick to dusk feedings. Patience wins.
• Skin abrasions and infections - Rough substrate and rockfalls scrape them up. Keep sand fine and rock stable. Treat bacterial spots in a hospital tank with a broad-spectrum antibiotic if they appear.
• Parasites (especially flukes) - Quarantine new arrivals. A freshwater dip can reveal flukes, and praziquantel works well. Be cautious medicating in display tanks.
• Medication sensitivity - Like many scaleless fish, they can react poorly to harsh treatments. If copper is necessary, use a testable, stable level and monitor closely, or consider alternatives under guidance.
• Water quality swings - Heavy, meaty feedings spike nutrients. Skim wet, siphon leftovers, and keep up on water changes.
• Obesity and fatty liver - Daily feedings or feeder fish diets cause problems. Stick to the every 2-3 day schedule with quality marine foods.