Butterfly stingaree

Where they come from

Butterfly stingarees (Urolophus papilio) are a small coastal ray from southern Australia. You see them on sandy bottoms and seagrass edges, half-buried and waiting for little crustaceans and worms to wander by.

That habitat tells you basically everything about how to keep them: wide footprint, soft sand, steady cool-ish marine temps, and peaceful surroundings.

Setting up their tank

Think "shallow lagoon" more than "reef tower." These rays spend their lives on the bottom, so floor space matters way more than height.

• Tank footprint: the biggest you can swing. For a single adult, I would not go under a wide 180+ gallon footprint, and bigger is genuinely better. If you can do a custom shallow tank, do it.
• Substrate: fine sand (sugar-sized). No crushed coral, no sharp gravel. If it scratches your hand, it will scratch the ray.
• Rockwork: keep it minimal and stable. Put rock on the glass or on supports, then add sand around it so the ray cannot undermine and topple it.
• Flow: moderate overall, but give them calm "rest zones" on the bottom. They hate being blasted in the face all day.
• Filtration: oversized and boring-reliable. Big skimmer, lots of biological capacity, and a way to export nutrients (water changes, refugium, etc.). Rays are messy eaters.
• Lid: cover the tank. Rays can and do launch themselves when spooked.

Water quality needs to be stable and clean, but the big gotcha with rays is oxygen and pH. Heavy feeding plus warm water plus a big animal equals low oxygen fast. Run strong surface agitation and keep your skimmer tuned.

What to feed them

If you buy one, assume it may not recognize pellets at first. Most come around, but you have to meet them where they are and build a routine.

• Best staples: raw shrimp, squid, scallop, marine fish flesh (not freshwater feeders), and quality frozen mixes meant for predators.
• For variety: live or fresh marine worms, small crabs, and other crustaceans (where legal and safe).
• Supplements: soak foods in a vitamin like Selcon a few times a week. I also add iodine occasionally, but I do not go crazy with it.
• How to feed: target feed with tongs or a feeding stick. Place the food right in front of the mouth so tankmates do not steal it.
• Schedule: smaller meals more often beats one huge dump. Juveniles eat frequently; adults can do every other day depending on body condition.

How they behave and who they get along with

Butterfly stingarees are generally calm, and most of the day you will see a pair of eyes and spiracles poking out of the sand. At feeding time they switch on and start "vacuuming" the bottom.

Tankmate choice is where people get burned. The ray is not aggressive, but it is easy to outcompete, easy to nip, and very easy to stress.

• Good tankmates: peaceful to semi-peaceful fish that do not pick at fins or eyes and are not frantic at feeding time. Think larger, calmer species.
• Avoid: triggerfish, puffers, large wrasses that flip sand constantly, most angels that like to sample fleshy things, and anything that will steal every bite before the ray finds it.
• Avoid also: big aggressive sharks/rays unless you have a huge system and a plan. Mixed elasmobranch tanks can work, but not as a "toss them together" situation.
• Inverts: assume most crabs, shrimp, and worms are ray food sooner or later.

Breeding tips

In home aquariums, breeding is uncommon. Urolophus rays are aplacental viviparous (they carry developing young internally), so it is not like egg-laying skates where you can spot a "mermaid purse" and call it a day.

If you ever do keep a compatible pair long term, the biggest "breeding tip" is honestly just longevity: stable water, generous footprint, and stress-free feeding. Most failures happen way before reproduction is even on the table.

Common problems to watch for

Rays are a little like canaries in the coal mine. They can look fine until they suddenly do not, so you want to catch the early signs.

• Poor appetite: often stress, bullying, or the ray never learned prepared foods. Fix feeding competition first, then look at parasites.
• Rapid breathing or hanging in high flow: usually low oxygen, high ammonia/nitrite, or pH issues. Check water now, not tomorrow.
• Disc abrasions and belly sores: almost always from rough substrate, sharp rock, or dirty bottom. Fine sand and a clean tank solve a lot.
• Nutritional deficiency: shows up as weight loss, weak swimming, or just a "tired" look. Add variety and vitamins, and do not rely on one food.
• Parasites and bacterial infections: tricky because you cannot just reach for copper. Work with ray-safe approaches (freshwater dips are not a blanket fix for marine rays, and formalin use needs real care).
• Electrical stray voltage and pump injuries: rays sit on the bottom and take the brunt of it. Use a GFCI, keep equipment maintained, and cover intakes.

If you want to succeed with this species, build the system around the ray, not the other way around. Big footprint, soft sand, stable water, and calm tankmates. Do that, and they are surprisingly hardy for an elasmobranch.