Southern banded guitarfish

Where they come from

Southern banded guitarfish (Zapteryx xyster) are a cold-to-cool water guitarfish from the temperate Pacific side of South America, most associated with sandy bays and coastal flats around Chile. In the wild they spend a lot of time half-buried, cruising the bottom for worms and crustaceans, and that shows up in captivity pretty much immediately.

Setting up their tank

Think of the tank like a big, chilled, sandy runway with clean water and lots of oxygen. The footprint matters more than the gallons on paper. These guys are all about bottom space and turning radius.

• Footprint first: a long, wide tank is the goal. For adults, you are realistically in custom system territory (public-aquarium style footprint).
• Sand bed: fine aragonite or silica sand, shallow to moderate depth. Avoid sharp crushed coral and anything that can scrape the belly.
• Rockwork: keep it minimal and stable. Put rock on the glass or on supports before sand so nothing shifts and pins the fish.
• Flow: you want good turnover and strong gas exchange, but avoid blasting the bottom where they rest.
• Chilling: plan a reliable chiller and a controller. Stable cool temps beat chasing a number day to day.
• Filtration: big skimmer, lots of biofiltration, and room to export waste (socks, rollers, etc.). They are messy eaters.

For water targets, I run them like a temperate marine system: normal marine salinity (around 1.024-1.026), a steady cool temperature, and very low nitrogen waste. They do not tolerate ammonia or nitrite at all, and they do way better when nitrate stays modest.

What to feed them

If you want this species to do well, your feeding game has to be on point. A guitarfish that eats hard from week one is a totally different animal than one you have to beg with food.

• Staples: strips of squid, shrimp (shell-on occasionally for roughage), scallop, marine fish fillet, and crab pieces.
• Great variety items: clams/mussels (especially to spark feeding), prawn, and the occasional live or freshly killed shore crab if you can source safely.
• Avoid: freshwater feeders (goldfish, rosy reds) and fatty freshwater meats. They can cause long-term problems.
• Supplements: soak pieces in a marine vitamin supplement sometimes. I also like rotating in foods naturally higher in trace nutrients (mollusks).

Target feed with tongs. It keeps them from eating sand, lets you control portions, and stops faster tankmates from stealing everything. Once they learn the routine, they will come right over and take food calmly.

How they behave and who they get along with

They are usually pretty chill, especially once settled, but they are still an elasmobranch with a strong feeding response. Most problems are not "aggression" so much as size mismatch or competition at feeding time.

• Best tankmates: other temperate species that ignore the bottom and do not pester them. Think calm, appropriately sized fish that will not outcompete them at every meal.
• Avoid: fin-nippers, pickers, and anything that wants to sample the edges of the fins. Also avoid triggers, many puffers, and most aggressive wrasses.
• Avoid: fast, greedy feeders that will constantly steal food (and make the guitarfish swallow sand trying to keep up).
• Rule of thumb: if it fits in their mouth, it is food. If it can bite them, it is a threat.

They spend a lot of time partially buried, then get active at dusk and around feeding time. They can spook and bolt, so keep the tank covered and do not decorate with sharp, pointy stuff in their flight path.

Breeding tips

Breeding guitarfish in home systems is uncommon, mostly because of space, temperature stability, and the challenge of keeping a mature pair long term. They are livebearers (aplacental viviparity), so you are looking at internal fertilization and then fully formed pups.

• If you ever get to a true pair: keep diet heavy and varied, and keep temperature swings small. Conditioning is mostly about long-term consistency.
• Provide lots of open sand. Stressed females do not do well with crowded floors or constant tankmate pressure.
• Have a plan for pups: separate rearing space, small foods (tiny shrimp, chopped seafood), and zero bullying from larger fish.

Common problems to watch for

Most issues with this species trace back to three things: warm water, dirty water, or rough environments. If you nail those, they are much more forgiving than people think.

• Refusing food after arrival: often transport stress, temp mismatch, or being harassed. Dim the lights, give sand, and offer smelly foods like clam or mussel.
• Ammonia/nitrite exposure: gill irritation, lethargy, rapid breathing. This is an emergency - big water changes and fix filtration immediately.
• Skin damage: red patches, scrapes on the belly, frayed fin edges. Usually from rough substrate, sharp rock, or bad handling.
• Bacterial infections: can follow tiny abrasions, especially if temps are too high for a temperate species.
• Parasites: flashing, rapid breathing, excess mucus. Treat in a way that is safe for elasmobranchs (no copper) and prioritize clean water and oxygenation.
• Nutritional issues: thin body despite eating, or fatty buildup from a repetitive diet. Rotate foods and use vitamins occasionally.