Longsnout armored searobin

Where they come from

Longsnout armored searobins (Paraheminodus longirostralis) are Indo-Pacific bottom dwellers that spend their lives prowling sand and rubble for small critters. They are one of those fish that look like they were designed by a committee: armored plates, a long snout, and those walking fin-rays they use to feel around like little fingers.

Most of the ones you see in the hobby come in as deeper-water/collected fish, so they can be a little touchy from shipping and decompression. That is a big part of why I call them "expert" even if their day-to-day needs are pretty straightforward once they are settled.

Setting up their tank

Build the tank around their lifestyle: slow cruising over the bottom, hunting by scent and touch. Give them real floor space and a sandy zone they can work. They do not need a rock wall to weave through, but they do need cover and calm.

• Tank size: I would not do one in less than 75 gallons, and 100+ is a lot nicer because they like room to patrol.
• Substrate: fine sand is your friend. Coarse crushed coral can rub them up, and they spend a lot of time pressed against the bottom.
• Aquascape: low rock piles and rubble edges, with open sand lanes. Think "flat hunting grounds" not "reef maze".
• Flow: moderate. You want good oxygenation and stable parameters, but not a sandstorm.
• Lighting: they do fine under normal reef lights, but they act bolder with some shaded areas.

Cover is more about security than hiding. A couple of caves/overhangs they can back into will lower stress, especially the first few weeks. I also like to provide a "quiet corner" where food naturally settles so the searobin can hunt without competing in the main current.

What to feed them

This is the make-or-break section. A longsnout armored searobin is a predator of meaty, crunchy little things. Many arrive skinny, and they will not compete well with fast pigs at feeding time. Your job is to get consistent calories into them without turning the tank into a nitrate factory.

• Best staple foods: chopped shrimp, clam, squid, scallop, and quality frozen "marine carnivore" mixes.
• If they are stubborn: live blackworms (salt acclimated), live ghost shrimp (gut loaded), or live shore shrimp can kickstart feeding.
• Treat/variety: small pieces of krill (not too often), fish flesh sparingly, and enriched mysis if they will take it.

Target feeding is your secret weapon. I use long tweezers or a feeding stick and place food right on the sand in front of them. They will often "walk" over, probe, then inhale it. Once they learn the routine, they usually come out when they see the stick.

Frequency depends on the individual. New or thin fish do better with smaller meals more often (even daily at first). Once they have filled out, I have kept them in good shape with 3-5 solid feedings per week, but that assumes they actually eat every time and nobody steals their share.

How they behave and who they get along with

They are calm, deliberate hunters. Most of the day is "walk, sniff, poke, pause." They are not a showy midwater fish, but they are fascinating if you like oddball behavior.

Compatibility is mostly about two things: will tankmates outcompete them for food, and can the searobin fit that tankmate in its mouth.

• Good tankmates: peaceful to semi-peaceful fish that do not live on the sand and are not crazy at feeding time (some tangs, larger wrasses that do not harass bottom fish, larger cardinals, some angels in big tanks).
• Risky tankmates: aggressive feeders like triggers, large hawkfish, boisterous dottybacks, and anything that constantly pokes at bottom dwellers.
• Do not keep with: tiny gobies, small shrimp, small crabs, and other bite-sized cleanup crew you care about. If it moves and fits, it is food.

Corals are generally fine because the fish is not a picker, but the hunting behavior can annoy corals placed on the sand. If you have LPS on the bottom, keep an eye out for the searobin bulldozing around them.

Breeding tips

Breeding this species in home aquariums is not something you see documented often. Searobins in general are egg scatterers with pelagic eggs/larvae, and the larvae are the hard part - tiny foods, specialized rearing, and a lot of losses even for people set up for it.

If you ever end up with a confirmed pair and see spawning behavior (more activity at dusk, pairing, quick rises in the water column), your best bet is to collect eggs with surface skimming and move them to a dedicated larval system. But realistically, most hobbyists keep them for the behavior, not for breeding projects.

Common problems to watch for

Most issues with longsnout armored searobins are not mysterious diseases. It is usually shipping damage, starvation, or injury from the environment.

• Not eating after arrival: common. Try low light, quiet tank, live foods to start, then transition to frozen on a feeding stick.
• Getting skinny despite feeding: tankmates stealing food, too little feeding frequency, or internal parasites. Watch the belly line and the thickness behind the head.
• Mouth/snout damage: can happen if they are in a tank with aggressive fish or if they slam into rock/glass when spooked.
• Belly abrasions and fin rot: usually from rough substrate or dirty bottom areas.
• Crypt/velvet sensitivity: many wild-caught bottom predators do poorly if you roll the dice. Quarantine and observation are worth the effort with a fish like this.