Barbedwire-tailed skate
Notoraja martinezi
The Barbedwire-tailed skate features a distinctive flattened, diamond-shaped body with a mottled brown to gray coloration and prominent barbed projections on its tail.
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About the Barbedwire-tailed skate
Notoraja martinezi is a deepwater skate from the eastern Pacific (Costa Rica down to Ecuador) that lives way down on soft bottoms. The tail is the giveaway - it is lined with strong, hooked thorns that really do look like barbed wire. This is absolutely not an aquarium fish; it is a cold, high-pressure deep-sea animal with basically no practical home care info because it is not kept in the hobby.
Also known as
Quick Facts
Size
47.5 cm TL
Temperament
Peaceful
Difficulty
Expert
Min Tank Size
0 gallons
Lifespan
unknown
Origin
Eastern Pacific (Costa Rica to Ecuador)
Diet
Carnivore - likely benthic prey (worms, crustaceans, small fishes)
Care Notes
- Plan for a big, low-and-wide system with a huge sand flat - think 8x3 ft footprint or larger for an adult, because they cruise and turn like a dinner plate, not a dartfish.
- Fine sand only (no crushed coral) and keep rockwork up on solid stands so nothing can topple onto the skate when it digs in; skip sharp décor or you will shred the disc edges.
- Keep it cool and stable: 60-68F, salinity 1.024-1.026, pH 8.1-8.4, and nitrate ideally under 10-20 ppm; they go downhill fast in warm, dirty water.
- Feed meaty marine foods on the bottom 3-5 times a week: pieces of shrimp, squid, clam, and marine fish flesh; use tongs or a feeding stick and add a vitamin/iodine supplement once or twice a week to prevent slow deficiency issues.
- Run serious oxygenation and turnover (big skimmer, lots of surface agitation) and avoid big temperature swings - heavy-bodied skates are oxygen hogs and will start breathing hard when something is off.
- Tankmates: think coldwater, non-aggressive fish that will not nip or steal food (some sculpins, lumpsuckers, chill cod-like fish) - avoid triggers, puffers, large wrasses, and anything that picks at fins or harasses the disc.
- Watch for the common mess-ups: fin edge abrasions, bacterial infections after sand/rock scrapes, and mouth injuries from grabbing spiny prey; if it stops eating, check temp and dissolved oxygen before you start tossing meds.
- Breeding is rare in home tanks but they are egg-layers (mermaid's purses) - if you ever find a case, move it to a separate chilled, well-oxygenated tank with gentle flow so it does not get fungus or crushed.
Compatibility
Good Tankmates
- Other peaceful skates or small, non-pushy rays (similar size and temperament) - they mostly ignore each other as long as you have a big, open sand flat and more than one hiding spot.
- Calm benthic sharks like bamboo or epaulette sharks - chill, bottom-oriented, and usually not interested in messing with a skate if everybody is well-fed and not cramped.
- Peaceful midwater fish that stay out of the sand zone like larger anthias or hardy chromis (not tiny) - they keep to the water column and do not compete for the skate's space.
- Reef-safe, mellow wrasses that are not bullies (think fairy or flasher types) - active swimmers that do not pick at the skate or steal every bite if you target-feed the skate.
- Bigger, well-behaved tangs or rabbitfish - good 'background' fish that cruise the rockwork and typically leave a peaceful skate alone.
- Non-aggressive bottom sitters that are too big to be food, like a large toadfish-type that is known to be mellow (and only if you have serious space) - works when both are relaxed and feeding is consistent.
Avoid
- Aggressive sharks and big predatory stuff (some larger catsharks, nurse sharks, big groupers) - they can harass the skate, outcompete it at feeding time, or straight-up injure it.
- Nippy, bitey fish like triggers and puffers - seen them chew fins and go after eyes and tail tips, and skates are basically sitting ducks on the sand.
- Fast, pushy feeders like big jacks/trevallies or hyper wrasses that mob food - the skate loses out and slowly wastes unless you are really on top of target feeding.
- Anything small enough to be inhaled (tiny gobies, small cardinals, small damsels) - skates are peaceful, but if it fits in the mouth, it is eventually on the menu.
Where they come from
Notoraja martinezi is a deepwater skate. Think cold, dark, and stable - the kind of fish that did not evolve around warm reef temps or daily swings. Most of the ones that show up in the trade are wild-caught and come in stressed from capture, shipping, and then being put into the wrong type of marine system.
If your setup is a typical 76-80F reef tank, skip this species. Warm water is one of the fastest ways to lose deepwater skates.
Setting up their tank
You are basically building a coldwater, heavy-filtration, open-floor system with a lot of oxygen and very little drama. They spend most of their time on the bottom, and their body is all soft edges and skin. Anything sharp or dirty in the substrate will show up as damage later.
- Tank size: think footprint first. A wide, long tank beats a tall one every time. For an adult skate, a several-hundred-gallon system with a big open bottom area is the realistic starting point.
- Temperature: coldwater. You will need a chiller and a controller. Keep temp steady, not bouncing day to day.
- Substrate: fine sand (sugar-sized to slightly larger). Skip crushed coral and rough aragonite.
- Rockwork: minimal and stable. Give them open lanes to cruise and room to turn without scraping.
- Flow and oxygen: strong gas exchange, lots of dissolved oxygen, but avoid blasting the bottom with a powerhead jet.
- Filtration: oversized skimmer, big bio capacity (live rock in a sump is fine, or dedicated bio media), and aggressive mechanical filtration you can clean often.
- Cover: a tight lid. Skates can surprise you when spooked, especially during acclimation.
I like to keep the display simple and do the fancy stuff in the sump: big skimmer, roller mat or socks you change a lot, carbon as needed, and a place to run extra bio media. The display stays skate-friendly and easy to vacuum.
Plan on doing bottom maintenance. Not obsessively, but regularly. Uneaten food and fine waste settle where the skate lives, and that is where skin issues start. I siphon the sand surface lightly and keep dead spots from forming behind any decor.
Never keep a skate in a tank that has copper medication in its history unless you are 100% sure the system is clean. Rays and skates are not forgiving about metals and mystery residues.
What to feed them
They are built for hunting small bottom animals. In captivity, you want meaty marine foods with variety, and you want them eating confidently before you relax.
- Staples: pieces of squid, shrimp, scallop, clam, marine fish flesh (not freshwater feeders).
- Great options: whole krill, chopped prawn, silversides (sparingly, and only good quality), mussel meat.
- Treats/variety: live or fresh-frozen marine worms when available (blackworms are freshwater and not my first pick for long-term).
- Supplements: a vitamin/HUFA soak a couple times a week goes a long way, especially for new arrivals.
- Feeding method: long tongs or a feeding stick. Place food right in front of them until they learn the routine.
New skates sometimes ignore food if it is dropped in the water column. Put it on the sand right by the nose, kill the pumps for a minute, and give them time. Dim lighting helps the first couple weeks.
Keep an eye on body condition. You want a nicely filled-out disc with no obvious pinched areas. If it is getting thin, it is usually either competition (tankmates stealing food), stress, or temperature being off for the species.
How they behave and who they get along with
They are generally calm and spend a lot of time resting. They can startle hard, though. Sudden light changes, banging on the glass, or boisterous tankmates will keep them on edge, and a stressed skate is a skate that stops eating.
- Good tankmates: other coldwater, non-aggressive fish that will not nip, and that will not outcompete at feeding time.
- Avoid: nippy fish, trigger-like personalities, anything that harasses the bottom, and anything that sees the skate as food.
- Also avoid: big fast feeders that vacuum up everything before the skate gets a chance (even if they are "peaceful").
Even "reef safe" cleaner shrimp and small crabs can become skate snacks, and the other direction can happen too: opportunistic crustaceans can pick at a resting skate if it is weak or has a wound.
One more compatibility note: think about stings and mouths. Skates are not out hunting your fish, but a small fish that sleeps on the sand can disappear. On the flip side, a large predatory fish can chew a skate up badly in one mistake.
Breeding tips
Breeding in home aquariums is possible with some skates, but with deepwater species like this, it is not something I would plan around. Sexing is doable (males have claspers), but getting a stable pair, seasonal cues, and then raising pups in coldwater conditions is a serious project.
If you ever see "mermaid purses" (egg cases), do not assume they are viable. Keep them in the same temp and salinity as the parents, with gentle flow, and be patient. Incubation can be long, especially in cold water.
Common problems to watch for
Most issues I have seen with skates trace back to three things: wrong temperature, dirty bottom conditions, or rough handling/acclimation.
- Refusing food: often stress, too-warm water, too-bright tank, or tankmates stealing. Fix the environment first, then troubleshoot diet.
- Skin abrasions and ulcers: usually from rough substrate, sharp rock edges, or ammonia/nitrite issues. These go downhill fast if the tank is not clean.
- Ammonia spikes: big meaty feeding plus a new system is a recipe for trouble. Mature bio filtration matters a lot here.
- Low oxygen: warm water holds less O2, and skates are heavy oxygen users. Strong surface agitation and a big skimmer help.
- Parasites from wild-caught animals: quarantine is hard with skates, but skipping it can introduce problems you will regret later.
Do not "dip" or medicate casually. Many common treatments that are fine for bony fish can be risky for elasmobranchs. If you have to treat, research specifically for skates/rays and be conservative.
My best practical advice: get them eating, keep them cold and stable, and keep the bottom clean. If you can do those three things, you are already ahead of most losses people have with deepwater skates.
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