Dofleini's lanternfish

Where they come from

Dofleini's lanternfish (Lobianchia dofleini) is a deepwater mesopelagic fish - one of those classic "night shift" animals that spends the day down in the dark and then moves up in the water column after lights-out to feed. You mostly see them referenced from offshore Pacific/Indo-Pacific deep pelagic surveys rather than reef collecting.

Setting up their tank

If you try one, think "deepwater holding system" more than "display reef." The biggest make-or-break factors are temperature control, oxygen, and low-stress lighting. You want the fish eating within days, not burning calories panic-swimming and fading out.

• Tank size: bigger is easier. I would not bother under 75-120 gallons, and longer tanks beat tall cubes because they cruise.
• Temperature: cool. Aim roughly 50-65 F (10-18 C) depending on source. Pick a target and keep it steady.
• Lighting: dim. Use a ramped schedule and keep bright white light off the tank. Blue-only, shaded areas, and lots of dark time help.
• Flow: gentle but constant. You want turnover and oxygenation without blasting them into a corner.
• Filtration: oversized bio + aggressive mechanical. These fish need frequent small feedings and that means nutrients.
• Oxygen: high. Strong surface agitation, skimmer, and/or oxygen injection if you know what you're doing.
• Decor: minimal. Open water with a few dark shelters or vertical structures for security. Avoid sharp rock piles they can smack into.

Quarantine is tricky because a bare, bright 10 gallon is basically a stress box for a lanternfish. If you quarantine (you should), set it up like the main system: dim, cool, covered sides, stable salinity, and mature filtration. I like blacking out three sides and giving them a calm corner with a piece of PVC.

What to feed them

These are micro-predators that pick off small drifting animals. Getting them onto prepared food is the whole game. Newly imported fish often only respond to moving prey at first, and they usually feed best at dusk and after lights-out.

• Best starters: live copepods, enriched adult brine (as a bridge food), small live mysids if you can get them.
• Frozen that often works (once settled): small mysis, chopped krill (tiny bits), calanus, enriched brine, finely chopped seafood mixes.
• Pellets/flakes: sometimes possible long term, but don't count on it. If they do take pellets, use tiny sinking marine pellets and feed after dimming lights.
• Feeding rhythm: 2-4 small feedings per day is better than one big dump. They are built to graze in the water column.

Watch the belly line. A lanternfish that is eating looks subtly fuller behind the pectorals. If it stays pinched for a week, you are on borrowed time. Also keep an eye on your nutrient levels - frequent feeding means you need to export waste like you mean it.

How they behave and who they get along with

They are shy, schooling-leaning fish that do best with calm tankmates and a predictable environment. In bright tanks they tend to hide, glass-surf, or just burn themselves out. At night they get bolder and will cruise midwater looking for food.

• Good tankmates: other coolwater, non-aggressive species that won't outcompete them for food.
• Avoid: fast pigs at feeding time (tangs, many wrasses), nippy fish, anything that will treat them like a snack, and anything that demands warm reef temps.
• Group vs single: if you can source multiple in good condition, a small group can settle better. But only if your system can handle extra feeding and you can verify everyone is getting food.

Cover the tank. Seriously. Deepwater fish can spook and launch, especially during acclimation or if a light snaps on. A tight lid saves lives.

Breeding tips

Breeding Lobianchia dofleini in home aquaria is basically in the "hasn't been done" category for hobbyists. They are pelagic spawners with a life cycle tied to deepwater cues, seasonal shifts, and larval stages that are not realistic to raise in a typical fish room.

Common problems to watch for

Most issues are stress and starvation problems wearing a disease mask. A lanternfish can look "clean" and still be failing because it never really acclimated to captivity.

• Refusing food: usually lighting, flow, temperature, or competition. Fix the environment first, then work food options.
• Rapid breathing and hanging in high-flow zones: low oxygen, too warm, ammonia/nitrite, or gill irritation.
• Banged-up noses/fins: spooking into glass or rockwork. Dim the tank, add background/side covering, reduce sudden movements.
• Skin/gill parasites: wild pelagic fish can arrive with flukes or protozoans. Treat carefully - they can be sensitive, and coldwater systems change medication behavior.
• Wasting away despite eating: internal parasites or the fish is burning too many calories from stress. Both happen.

If you are serious about keeping this species, plan the system around the fish, not the other way around. Stable cool water, dim light, high oxygen, and lots of small feedings are what separates the rare successes from the common "they lasted a week" stories.