Moore's sand eel

Where they come from

Moore's sand eel (Yirrkala moorei) is one of those oddball marine eels that spends a lot of its life buried in sand with just the head poking out. They show up in the Indo-Pacific region and are tied to sandy flats and rubble zones where they can disappear fast when spooked.

If you are expecting a rock-cave moray vibe, this is a different animal. Think ambush hunter that wants a runway of sand more than a pile of rocks.

Setting up their tank

This is an expert fish mostly because of two things: escape risk and feeding. The tank itself is straightforward if you build it around their behavior - deep sand, stable water, and zero gaps in the lid.

• Tank size: I would not do this in less than 75 gallons, and 120+ is way less stressful long-term (more sand footprint, more stable water).
• Sand bed: 4-6 inches of fine sand. They want to bury, not wedge into rocks.
• Rockwork: Keep it stable and leave open sand lanes. Put rocks on the glass or on supports, not sitting on sand that can shift when the eel digs.
• Flow: Moderate, but avoid blasting the sand bed into dunes. Random flow is fine if you shield the sand a bit.
• Filtration: Oversize your skimmer and run mechanical filtration you will actually clean. These are messy, high-protein feeders.
• Lid: Tight. Every hole blocked. Plumbing cutouts, feeding doors, cable gaps - all of it.

I like to give them at least one or two "starter burrows" by placing a short section of PVC (like 1-1.5 inch) under the sand at an angle. Sometimes they ignore it, sometimes it becomes their favorite spot, but it helps them settle in during that first stressful week.

What to feed them

Feeding is the make-or-break part. Many sand eels come in underfed and stressed, and they do not always recognize prepared food right away. You will likely need to train them onto frozen.

• Best starters: live or very fresh foods that move - small live fish only if you are experienced and can source safely, otherwise live ghost shrimp can work as a transition.
• Frozen staples once trained: silversides (appropriately sized), lancefish, mysis for smaller individuals, chopped shrimp, squid, and marine fish flesh.
• How to offer: feeding tongs near the burrow entrance, small movements to simulate life. Some will only strike if the food is "swimming".
• Frequency: smaller meals 3-4 times a week beats one giant feeding. Watch body condition and adjust.
• Vitamins: soak frozen food in a vitamin supplement a couple times a week. It helps when the diet is limited early on.

A good sign you are on the right track is when the eel starts showing up predictably at feeding time. Mine learned the tongs meant dinner and would rise out of the sand instead of doing the lightning strike from a hidden position.

How they behave and who they get along with

Most of the day you will see a head sticking out of sand, watching everything. They can be shy at first, then surprisingly bold once they settle. They are still predators, though, and their whole setup is built around eating passing fish and crustaceans.

• Good tankmates: robust fish that will not fit in the eel's mouth (tangs, larger wrasses, rabbitfish, larger angels in big tanks).
• Avoid: tiny gobies, firefish, small blennies, ornamental shrimp, and basically any "cute small cleanup crew" you care about.
• Other eels: not my favorite mix unless you have a large system and know each animal well. Competition at feeding can get weird fast.
• Inverts: snails and larger hermits are usually ignored, but anything shrimp-shaped is a gamble.

Breeding tips

Breeding Yirrkala moorei in home aquariums is basically in the "nice dream" category. Eels have complex larval stages (leptocephalus larvae) that drift in the plankton, and raising them is a whole specialty on its own.

If you ever end up with two that tolerate each other and you see pairing behavior, the best thing you can do is keep the system stable, feed well, and document it. But I would not buy them expecting breeding success.

Common problems to watch for

• Escape attempts: usually triggered by poor lid coverage, bullying, sudden light changes, or big swings in salinity/temperature.
• Hunger strikes: common after shipping. Give them sand to hide in, keep traffic low around the tank, and focus on enticing foods and calm feeding sessions.
• Injuries on the snout: happens when they launch into glass or try to push through lids. Fix the cause first, then keep water clean to prevent infection.
• Poor water quality from heavy feeding: expect nitrate to climb if you are not on top of skimming, water changes, and mechanical filtration maintenance.
• Parasites: wild-caught predators can bring baggage. If you see flashing, heavy breathing, or excess mucus, be ready with a plan (and remember many meds are not reef-safe).

My general rule: if the eel is buried, breathing normally, and coming up for food on a routine, you are winning. Most problems start when they are stressed and roaming the glass at odd hours. That is your early warning to check tankmates, lid gaps, and your last few test results.