Shiner anchovy

Where they come from

Shiner anchovies (Encrasicholina intermedia) are little open-water schooling fish from coastal Indo-Pacific areas. Think warm, salty water, lots of current, and a life spent cruising in the water column picking plankton out of the flow.

In the hobby they show up as "baitfish" style marine fish, and that background explains basically everything about them: they stress fast, they need space to move, and they live or die by steady feeding and clean, oxygen-rich water.

Setting up their tank

If you want these to last, set the tank up for a midwater school, not a rockscape showpiece. They want a long run to swim and clear lanes to turn as a group.

• Tank size: bigger than you'd think. A 4 ft tank is the bare minimum for a small group, and a 6 ft tank is where they start acting normal.
• Shape matters: long and wide beats tall. They use horizontal space.
• Open water: keep the center open. Put rockwork low and to the sides so they do not pinball into it.
• Flow and oxygen: strong, broad flow plus aggressive surface agitation. I run more aeration than I would for most reef fish.
• Filtration: oversized skimmer and lots of mechanical filtration you can change often (filter socks/roller). They are messy eaters and you will be feeding a lot.
• Lighting: moderate. Too bright with no cover can make them skittish. A bit of shaded area helps.

I also like to give them a "calm corner" behind a rock finger or a bit of macro where the flow breaks. They spend most of the day in the current, but having a place to slide into when startled cuts down on frantic crashing.

What to feed them

These are plankton pickers with a fast metabolism. The number one reason people lose them is not feeding often enough, or offering food that is too big or sinks too fast.

• Best staples: enriched baby brine, adult brine (enriched), copepods, calanus, small mysis, finely chopped krill, fish eggs, and small marine pellets once they accept them.
• Feed frequency: multiple small meals. I aim for 3-6 feedings a day early on, then at least 2-3 once they are settled and taking prepared foods.
• Food size: tiny. If you can clearly see each piece from across the tank, it is probably too big.
• Keep it in the water column: use flow to keep food suspended. If everything hits the bottom, they will miss half of it and your nutrients will climb.

Getting them onto pellets is possible, but do not force it. I start by mixing very small pellets into a cloud of frozen plankton so they accidentally take some. Once a few learn, the rest usually follow.

How they behave and who they get along with

They are classic schooling fish. In a proper group they look relaxed and coordinated. Kept in too small a group, they act twitchy and slam into the glass.

• Group size: more is better. A small school acts way more confident than a pair or trio.
• Temperament: peaceful, nervous. They do not hold territory.
• Tankmates: calm reef fish that ignore them work best (gobies, blennies, smaller wrasses, cardinals, peaceful anthias).
• Avoid: anything that sees them as food (most groupers, big wrasses, lionfish, many triggers), and hyper-aggressive fish that keep them pinned (dottybacks, damsels in small tanks).

They do best in a tank where you are not constantly sticking hands and tools in. Every big disturbance resets them a bit. If you do maintenance, move slowly and keep the room light on so you are not a sudden silhouette.

Breeding tips

Spawning in home aquariums is possible in the broad sense (they are pelagic spawners), but raising the larvae is the hard part. The eggs and larvae are tiny and need live plankton on a schedule that looks more like a marine fish hatchery than a typical reef tank.

• What you might see: early morning spawning behavior, tighter schooling, quick dashes, and then nothing (eggs are nearly invisible).
• If you want to try: dedicate a separate rearing setup with greenwater, rotifers, and copepod nauplii ready before you ever see eggs.
• Egg/larvae collection: a surface egg collector or gentle overflow to a screened catch container can help, but you need very calm handling.

Common problems to watch for

• Shipping and acclimation losses: they come in beat up sometimes. Look for clear eyes, intact fins, and a fish that can hold position in the flow.
• Jumping: especially first week and at lights on/off. Use a tight lid and block tiny gaps around plumbing.
• Starvation: pinched belly, hollow behind the head, hanging in corners. Increase feeding frequency and offer smaller foods.
• Oxygen crashes: rapid gilling, hanging at the surface, school falling apart. Add aeration, increase surface agitation, clean clogged socks, and check skimmer/return flow.
• Glass surfing and crashing: usually stress from too-small group, too-small tank, too much light, or aggressive tankmates.
• Parasites: marine ich and flukes can hit them hard because stress lowers their resistance. Watch for flashing, white dots, and heavy breathing.

If you build the tank around their needs (space, flow, oxygen, frequent small feedings, and a real school), they are one of the coolest "living baitball" fish you can keep. If you try to keep them like a standard reef fish, they usually do not last long.