Black verilus

Where they come from

Black verilus (Verilus sordidus) shows up around rocky reef and rubble zones where there are lots of hiding spots and ambush points. Think ledges, cracks, and mixed sand-and-rock patches rather than open, pretty coral gardens. That habitat tells you a lot about how they want to live in your tank: tucked away, watching, and coming out on their terms.

Setting up their tank

This is an expert fish mostly because it does badly in immature systems and it hates being the center of attention. Give it a stable, established marine tank and build the rockwork like a maze. You want multiple deep retreats where it can fully disappear, plus a couple of clear "runways" it can patrol.

• Tank size: bigger is better. I would not bother under 120 gallons, and 180+ makes life easier.
• Rockwork: lots of caves and tight crevices, but keep it stable (zip ties/reef epoxy if needed). They will wedge themselves in.
• Flow: moderate with calmer pockets behind rock. Don’t blast the whole tank like an SPS raceway.
• Lighting: they do fine under reef lighting, but they act bolder with shaded areas and overhangs.
• Filtration: oversized skimming and strong export. Predatory eaters mean messy waste.
• Lid: tight. If it spooks at night, it can launch.

Acclimation matters. Dim the lights, slow drip, and do not chase it around with a net. Use an acclimation box if you can, especially if you already have established fish that will investigate or harass it.

What to feed them

These are the kinds of fish that do best when you treat feeding like a routine, not a spectacle. Mine learned the schedule fast, but it only happened after it felt safe in its cave network. Start with foods that smell strong and move a bit in the current.

• Best starters: thawed mysis, chopped raw shrimp, chopped clam, squid strips, krill (sparingly), and good marine carnivore blends
• If it is picky: live ghost shrimp or live blackworms can get it going, then transition to frozen
• How I feed: long feeding tongs or a turkey baster near its hide, then gradually move the food out into the open over weeks

Skip the temptation to overfeed because it finally came out. Small, frequent feedings are easier on water quality and digestion. If you have tangs or wrasses that mob food, distract them on the other side of the tank, then target-feed the verilus.

How they behave and who they get along with

Expect a shy fish that turns into a confident landlord once it claims a cave. It will watch everything, and it will absolutely eat what fits in its mouth. It is not "mean" in the way triggers are mean, but it will defend its space and it does not tolerate constant pushy tankmates.

• Good tankmates: larger, steady fish that mind their business (bigger tangs, larger angels in big tanks, some larger wrasses)
• Risky: hyperactive food thieves, fin nippers, and anything that tries to share caves (many dottybacks, some basslets, pushy hawkfish)
• Nope: small fish, small shrimp, and small crabs - they are food sooner or later
• Reef safety: assume "not reef safe" with small cleanup crew and tiny fish. Corals usually get ignored, but the tankmates are the issue.

One thing that helps a lot: give it multiple caves so it does not feel like it has to defend the only good spot. I have seen a night-and-day difference in aggression just by adding more rock cover and breaking up sight lines.

Breeding tips

Breeding in home aquariums is not something you should count on with Black verilus. Even if you end up with a compatible pair, larval rearing for marine species like this is its own project (live foods, specialized setups, lots of losses while you learn).

Common problems to watch for

• Refusing food after purchase: usually stress, lack of hiding, or getting outcompeted at feeding time
• Slow weight loss: it is eating, but not enough (or food is too lean). Increase feeding frequency and offer richer marine meaty foods
• Crypt/velvet: they can be sensitive shippers. Quarantine is your friend, but plan around copper sensitivity and stress
• Injuries from wedging into rock: torn fins and scrapes happen when they spook. Keep rock stable and avoid startling the tank at night
• HLLE-like pitting: often tied to nutrition, chronic stress, or water quality. Vitamins, varied diet, and clean water usually help

My general rule with this fish: if you can keep your parameters steady and your hands out of the tank, you are halfway there. Most failures I have seen were not one big mistake, but a bunch of small disruptions stacked together.