Spottail pinfish
Diplodus holbrookii
Spottail pinfish exhibit a silver body with distinctive black spots along the lateral line and a prominent dorsal fin.
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About the Spottail pinfish
A sturdy porgy with a big inky spot at the base of the tail and a steel-blue back, spottails cruise seagrass beds picking at little crabs and other crunchy snacks. They get a lot bigger than people expect and stay busy swimmers, so they need real room. If you want a personality fish for a big salt tank, this one is fun to watch but not a beginner choice.
Also known as
Quick Facts
Size
46 cm
Temperament
Semi-aggressive
Difficulty
Advanced
Min Tank Size
180 gallons
Lifespan
8-11 years
Origin
Western Atlantic - US East Coast to northern Gulf of Mexico
Diet
Omnivore - small inverts and algae; accepts marine pellets, mysis/krill, chopped seafood
Water Parameters
23-28°C
8.1-8.4
12-20 dGH
Need a heater for this species?
This species needs 23-28°C in a 180 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Think 75 gal for a single juvenile and 120+ gal for an adult, with open swim space, some rock ledges, and a sand patch. They jump - use a tight lid.
- Run full-strength seawater 1.023-1.026 at 72-76 F and pH 8.0-8.4 with strong aeration. They eat like pigs, so oversize the skimmer and swap filter socks often.
- Feed 2-3x/day a mix of chopped shrimp, clam, mussel, mysis, quality marine pellets, and some nori or macro. Toss in hard-shelled items weekly to help keep the teeth worn down.
- Not reef safe - they will nip corals and raid snails, crabs, and shrimp. House with robust, fast fish that wont fit in their mouth, not delicate or tiny species.
- Keep one per tank unless you have a huge system; they posture and spar with similar-shaped fish. Avoid slow or long-finned tankmates that get outcompeted at feeding time.
- Most are wild-caught and come with hitchhikers - quarantine 4-6 weeks and use praziquantel for flukes/worms. Watch for flashing, yawning, clamped fins, and rapid breathing.
- If collected from cooler inshore water, start them around 72-74 F and raise slowly over a few weeks; sudden jumps into the 80s right after capture can knock them down.
- Breeding is a no-go in home tanks - they spawn offshore and the larvae are planktonic. Dont expect pairing or nest behavior.
Compatibility
Good Tankmates
- Tough damsels and sergeant majors that can keep pace and wont get pushed off food
- Fast, medium wrasses like Halichoeres and Thalassoma that zip around all day
- Similar-sized tangs and rabbitfish that are quick, alert, and not easily nipped
- Squirrelfish and soldierfish that mind their own business but are too spiny and sturdy to hassle
- Medium grunts or porkfish that are robust and schooly, good match for an active tank
Avoid
- Tiny or timid fish that look like snacks, like small gobies, blennies, mandarins, or pipefish
- Slow fish with long, flowy fins that invite nipping, like lionfish, bannerfish, moorish idol, or delicate butterflies
- Big bullies or outright predators that will harass or eat them, like triggerfish, large groupers, big eels, or snappers
Where they come from
Spottail pinfish are western Atlantic sparids. You see them from the Carolinas and Florida through the Gulf of Mexico, around the Caribbean, and down toward Brazil. Juveniles hang around seagrass beds and sandy bays, and the bigger ones cruise patch reefs and rubble zones. That black spot at the base of the tail gives them away.
Setting up their tank
They get big for a home tank and they never stop moving. Plan on a 6- to 8-foot tank. I would not house an adult in anything under 180 gallons, and more is better if you want tankmates. Think fish-only with live rock. They are not reef safe and they will sample anything that looks edible.
- Temperature: 70-76 F (they handle cooler water better than tropical heat)
- Salinity: 1.023-1.026
- pH: 8.0-8.4
- Alkalinity: 8-11 dKH
- Flow: medium to strong, lots of oxygen
- Lighting: regular fish-only lighting is fine
Give them room to sprint and turn. Open water in the front, solid rockwork in the back with arches and a few tight slots they can nose into. Fine sand is great because they like to pick through it. Run a strong skimmer and oversized biofiltration. They eat like linebackers and make a mess.
They jump. Use a tight, weighted lid or a well-fitted mesh cover.
Not reef safe. They will nip at corals and will absolutely go after shrimp, crabs, snails, and clams.
If your room runs warm, budget for a chiller. Keeping them at tropical temps long term leads to stress and disease.
What to feed them
Omnivorous and opportunistic. Mine learned very quickly that anything I clipped or dropped was fair game. Offer a mix of meaty foods and greens, and feed smaller portions 2-3 times a day. They appreciate chewy, shelly items they can work on.
- Chopped shrimp, squid, scallop, and fish
- Clam or mussel on the half shell (great enrichment)
- High-quality marine pellets and sticks (mix sizes so they can grab and crush)
- Mysis and enriched brine as treats, not staples
- Marine algae sheets (nori) and bits of blanched greens
- Occasional live blackworms or small crabs for foraging behavior
Soak a couple meals per week in a vitamin mix and omega-3s. It keeps color up and helps avoid ragged fins and lateral line issues.
How they behave and who they get along with
Spottail pinfish are busy, nosey, and a little pushy. Juveniles hang together, but adults can be scrappy with similar-shaped fish. They constantly pick at rocks and substrate, so delicate tankmates get stressed fast.
- Good tankmates: robust tangs, large angels, big fairy/Thalassoma wrasses, bigger butterflies, larger squirrelfish, and similar-sized dither fish in a roomy FOWLR.
- Use caution: triggers and puffers (food competition and nipping wars), medium groupers and snappers (might see your pinfish as lunch if sizes mismatch).
- Avoid: small gobies/blennies, seahorses, tiny reef fish, ornamental shrimp and crabs, and coral setups in general.
If you want more than one, add a small group of juveniles to a very large tank at the same time. Mix of sizes helps. Expect sorting and some chasing at feeding time.
Breeding tips
They are open-water spawners that release eggs and sperm into the water column, usually seasonally. Larvae are tiny and drift. That combo makes home breeding unrealistic. Public aquariums with round tanks and plankton-rearing setups have a shot; most of us do not. If you ever see pre-spawn circling and color flashes at dusk, just enjoy the show and run extra filtration that night.
Common problems to watch for
Most issues come from heat, cramped quarters, and parasites from wild collection. Quarantine pays off with this fish.
- External parasites: Cryptocaryon (marine ich) and flukes show up as flashing, excess mucus, or labored breathing. I treat flukes with praziquantel and use copper or chloroquine for ich in a separate QT.
- Internal worms: stringy white poop and eating without gaining weight. Prazi or fenbendazole in QT helps.
- Bacterial scrapes: they hit rock at full tilt sometimes. Keep water clean and flow high; most scrapes heal fast.
- Heat stress: pacing, gulping at the surface, and sudden refusals to eat. Bring temps back down slowly and boost aeration.
- Food dominance: they outcompete shy fish. Use feeding rings, multiple stations, and spread the food out.
Quarantine new arrivals 4-6 weeks. They often come in with flukes. Treat, fatten them up, and make sure they are slamming pellets before they meet the display.
Move them with a container, not a net. Dorsal spines snag easily and they thrash. A specimen box saves fins and fingers.
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