Chilean round ray

Where they come from

The Chilean round stingray is a temperate-water coastal ray from the Humboldt Current zone along Peru and Chile. Think cool, nutrient-rich water, sandy bays, river mouths, and quiet surf flats. They spend a lot of time half-buried, waiting to pounce on crustaceans and small fishes.

Setting up their tank

This is a temperate marine ray. If your fish room runs at reef temps, this is not the species for that system.

• Footprint first: aim for at least 8 x 3 ft (2.4 x 0.9 m). Bigger is better. I would call 400-600 gallons the realistic starting range for an adult.
• Chiller: plan for 14-18 C (57-64 F) as the target band. They tolerate up to ~20 C (68 F) short term, but living warm shortens their lifespan.
• Salinity 1.024-1.026, pH 8.0-8.3, undetectable ammonia and nitrite, nitrate ideally under 10-20 ppm.
• Substrate: 2-3 inches of fine, rounded sand (sugar-size aragonite or smooth silica/pool filter sand). No crushed coral or sharp gravel.
• Aquascape: keep it open. A few low, smooth rock piles for line of sight breaks. No jagged rock. Rays need uninterrupted floor space.
• Flow and oxygen: strong gas exchange and high dissolved oxygen. Broad, gentle flow. Guard every intake and overflow with foam or mesh.
• Filtration: oversized skimmer, big refugium or algae reactor, and a canister or sump section for mechanical media you can rinse often. Rays are messy.
• Lids: tight-fitting cover. They can surge up walls during startled bursts.
• Lighting: subdued is fine. They do not care about reef-level lighting.

Acclimate slowly. I drip-acclimate in a lidded tub for 60-90 minutes with a chiller coil or ice bottles to keep temperature steady, then move the ray by container, not a net.

What to feed them

New arrivals often ignore food for a few days. Start with movement and smell, then switch to clean, marine-based items.

• Good starters: live blackworms (rinsed well), live ghost shrimp, or gut-loaded shore shrimp to trigger feeding.
• Staples: fresh or high-quality frozen pieces of shrimp, squid, clam, scallop, sand eels, smelt, and marine fish flesh. I avoid oily fish like salmon as a staple.
• Prep: cut to bite-size strips and offer on feeding tongs right at the sand so they can pin it.
• Supplements: soak foods in a marine vitamin mix (I use Selcon or similar) a few times a week. Rotate items to avoid thiaminase-heavy exclusives like smelt/silversides.
• Schedule: juveniles daily in small portions; adults every other day. Aim for a rounded belly that flattens by the next feeding.

How they behave and who they get along with

They are calm, bottom-oriented, and spend a lot of time buried with just eyes and spiracles showing. Mine was most active at dawn and dusk, cruising the glass edge for snacks once he learned the routine.

• Best setup: species-only or with other peaceful, temperate fish that ignore the bottom. Think cool-water gobies, small wrasse-like temperate species, or nothing at all.
• Avoid: triggers, puffers, large angels, and pickers that nip at fins or spiracles. Also avoid hyperactive predators that will outcompete them.
• Inverts: crabs, shrimp, and small snails are likely snacks. Urchins and large starfish are hit-or-miss.
• Multiple rays: only in very large tanks. Add at the same time and watch for disc-nipping or food competition.

Breeding tips

They are livebearers. Sexing is easy: males have claspers. Breeding in home aquaria is rare but not impossible with this genus if you give them room, stable cool temps, and a calm social setup.

• Seasonal cues: a gentle winter-summer temperature swing (for example, 14-15 C in winter to 17-18 C in summer) and a matching photoperiod shift can help. Change slowly over weeks.
• Conditioning: heavy feeding with shell-on marine foods for calcium and varied proteins. Keep water pristinely clean.
• Courtship: males follow and nudge the female, sometimes nipping. Separate if you see persistent damage.
• Gestation: months, not weeks. Provide deep, clean sand and minimal stress.
• Pups: they are miniature copies. Offer tiny strips of shrimp, mysis, or live blackworms right away. Protect them from intakes and from adults in smaller systems.

Common problems to watch for

• Heat creep: room warms up, chiller cannot keep up. Use a properly sized chiller and insulate lines. A temperature controller with alarms is worth it.
• Abrasions on the disc: usually from coarse substrate or rock. Switch to finer sand, smooth sharp edges, and keep water ultra-clean while healing.
• Not eating: check temperature, nitrate, and dissolved oxygen. Try live offerings, then transition to prepared. Parasites are common on wild imports.
• Flukes and external parasites: flashing, excess mucus, cloudy eyes. Treat in quarantine with praziquantel. Freshwater dips are stressful and risky for rays.
• Internal worms: weight loss despite eating. Use metronidazole or fenbendazole in food in a hospital setup.
• Nutritional gaps: exclusive silversides lead to thiamine deficiency. Rotate foods and use vitamin soaks.
• Stray voltage: rays are sensitive. Use a GFCI and a grounding probe.
• Medication mishaps: copper and formalin can be lethal. Research ray-safe doses before any treatment.
• Poor oxygenation: rapid breathing or surface gulping. Increase aeration, reduce temperature, and clear clogged mechanical media.