Smooth bandfish

Where they come from

Smooth bandfish (Owstonia psilos) are one of those deepwater oddballs that make you wonder how they even end up in the hobby. They come from deeper reef slopes and rubble zones in the Indo-Pacific, where the light is dim, the current is steady, and food comes by in little pulses.

That deepwater background explains a lot: they spook easily, they do not love bright lighting, and they often arrive stressed from collection and shipping.

Setting up their tank

Think of this fish as a shy planktivore that wants a calm, secure home base and clean, stable water. If you try to keep it in a loud, busy reef with boisterous feeders, you will spend your time watching it hide and lose weight.

• Tank size: I would not bother under 40-50 gallons, and bigger is easier if you have active tankmates.
• Aquascape: lots of caves and overhangs, plus a few vertical crevices. They like to hover near shelter and back into it fast.
• Flow: moderate, not blasting. You want food to stay in the water column without turning the fish into a kite.
• Lighting: dim to moderate. If your reef is bright, give them shaded areas (overhangs, tall rock, macro patches).
• Cover: tight lid. Deepwater, shy fish + night spooks = jump risk.

I like a mellow acclimation: lights low, plenty of hiding spots even in QT (PVC elbows help), and I keep the first couple days very quiet. Sudden movement in front of the glass can send them into the rocks.

Water quality wise, they are not forgiving. Keep nutrients reasonable, keep oxygen high, and avoid big swings in salinity and temperature. Stability beats chasing numbers.

What to feed them

Getting them eating is the whole game. Once they learn your feeding routine, they are not hard to keep, but the first couple weeks can be rough.

• Starter foods: live baby brine (enriched), live copepods, or live mysis if you can get it.
• Transition foods: frozen mysis, calanus, finely chopped krill, roe, and good small pellet once it is confident.
• Feeding style: small portions 2-4 times a day beats one big dump.
• Targeting: a turkey baster or feeding tube lets you place food right in their hover zone near cover.

Watch the belly and the back behind the head. With bandfish, weight loss can sneak up on you because they are naturally slim. If the fish looks pinched and stops coming out, you need to change something fast: quieter tank, more frequent feedings, or different food size.

How they behave and who they get along with

They are peaceful, a little spooky, and mostly hover-and-dart rather than cruise around. In a calm tank, you will see them out a lot more than you expect. In a hectic tank, they become a phantom.

• Good tankmates: small, non-pushy planktivores and peaceful reef fish (think small gobies, assessors, some fairy/flasher wrasses, small anthias if everyone is well-fed).
• Avoid: aggressive feeders (bigger wrasses, dottybacks, damsels), boisterous tangs in small tanks, and anything that treats new fish like a chew toy.
• Predators: obviously no hawkfish, big groupers, or large predatory wrasses.

They generally ignore corals and inverts. The only time I have seen issues is with very small ornamental shrimp if the fish is hungry and the shrimp is tiny, but it is not a dedicated shrimp hunter.

Breeding tips

Captive breeding is basically uncharted for this one in home aquariums. They are deepwater, likely spawn in the water column, and the larval stage would be a serious plankton project.

If you ever try, your best shot is a bonded pair in a quiet species tank, heavy feeding, and a dusk lighting ramp. But honestly, most of us are focused on long-term survival and getting a solid feeding response.

Common problems to watch for

• Refusing food after arrival: usually stress, bright lights, or competition. Dim the tank, add cover, offer live foods, and feed small amounts often.
• Slow starvation: the fish eats a little but not enough. Track body condition weekly and adjust feeding frequency.
• Jumping: tight lid and cover gaps around plumbing.
• Shipping damage and bacterial issues: frayed fins, cloudy eyes, red marks. Quarantine and be ready to treat if it declines.
• Flukes and external parasites: flashing, rapid breathing, clamped fins. QT observation helps a lot here.

The big takeaway with Owstonia psilos is that you are babysitting the first month. Give it a calm setup, feed like you mean it, and keep the tank politics peaceful. Once it is confident and eating prepared foods, it turns into a really rewarding, unusual display fish.