Hairy blenny

Where they come from

Hairy blennies (Labrisomus nuchipinnis) are Caribbean fish. Think shallow rocky reefs, rubble, and pockets of algae where they can wedge themselves in and watch the world go by. They are built for that life: camo pattern, big personality, and a habit of sitting still until food wanders close.

Setting up their tank

If you set up the tank like a little chunk of reef rock with lots of hiding cracks, you are already halfway there. These blennies like territory and cover more than open swimming space.

• Tank size: I would start at 30 gallons for one. Bigger is easier if you want other bottom-dwellers too.
• Rockwork: lots of caves, overhangs, and tight crevices. They love a "favorite hole".
• Flow: moderate. Give them calmer pockets behind rocks so they can perch without getting blasted.
• Substrate: sand is fine, rubble zones are even better. They spend a lot of time near the bottom and in rock gaps.
• Filtration: they are messy eaters, so a decent skimmer and regular nutrient export helps a lot.

Give them time to settle. The first week or two they may act like a grumpy little gargoyle that only comes out at feeding time. Once they pick a home, they get bolder.

What to feed them

These are not the classic algae-grazing "lawnmower blenny" type. Hairy blennies lean carnivorous. Mine did best on meaty foods and would ignore most veggie-heavy stuff.

• Frozen: mysis, chopped krill, brine (as a treat), clam, and mixed reef blends
• Prepared: sinking marine pellets and small carnivore wafers (start small and see what they accept)
• Live: amphipods and copepods are a nice bonus, especially in an established tank

I have had better luck feeding smaller amounts more often rather than one big dump. They will overeat if they can, and the leftovers foul the water fast.

How they behave and who they get along with

Hairy blennies are perch-and-pounce fish. They sit, watch, and make quick little dashes for food. Personality-wise, expect "bold but not a nonstop swimmer."

• Toward fish: usually fine with peaceful mid-water fish, but they can be territorial with other bottom perchers
• Toward similar fish: other blennies, gobies, and hawkfish-looking types can trigger squabbles in smaller tanks
• Toward inverts: bigger shrimp and crabs are often ignored, but tiny shrimp (and very small ornamental crabs) can be seen as snacks
• Toward corals: generally reef-safe in the sense that they do not go munching coral polyps, but they may knock frags if they wedge into spots

They are pretty good at holding their ground, but they are not invincible. Avoid housing them with very aggressive fish that patrol the rockwork (big dottybacks, nasty damsels, or larger wrasses that bully). A hairy blenny that gets pinned into hiding stops eating.

Breeding tips

Breeding them in a home aquarium is possible but not something most people accidentally pull off. They are cave spawners in the wild, with eggs laid in a protected spot and the male typically guarding.

• Provide multiple snug caves (small PVC elbows hidden in rock work too) so a pair has options
• Keep them well-fed on meaty foods and stable day-night lighting
• If you ever see one refusing to leave a cave and fanning inside, check for eggs

Common problems to watch for

Most issues I have seen with hairy blennies come down to two things: stress from tankmates and not getting enough food because faster fish outcompete them. They are hardy once settled, but the first month tells the story.

• Not eating at first: common after shipping. Dim the lights, offer frozen mysis and small meaty bits, and target feed near their hideout
• Jumping: usually a startled fish or a new fish exploring. Lids and covered gaps fix this
• Territorial fights: torn fins and constant posturing happen if you cram multiple perch fish into the same rock pile
• Ich/velvet: they are not immune. Quarantine if you can, and do not ignore fast breathing or flashing
• Bloat/constipation: can happen if they gorge on large dry pellets. Mix in frozen foods and keep pellet size small