Blotched catshark

Where they come from

Blotched catsharks (Scyliorhinus meadi) are deepwater Atlantic catsharks. They are the kind of animal that spends its life cruising dim, cool bottom water, picking up scent trails and pouncing on small prey. That's why they act so different from the typical reef fish people are used to.

Setting up their tank

This is an expert-level shark mainly because of the system demands, not because it is "hard" in the daily routine. Think big footprint, smooth interiors, heavy filtration, and cooler water than most marine tanks.

• Tank size: plan for a large, wide footprint system. A long, open bottom area matters more than height.
• Aquascape: keep rockwork minimal and stable, and leave turning room. No sharp rock points, no narrow caves.
• Substrate: fine sand. Coarse gravel will scrape them up over time.
• Flow and oxygen: moderate flow with strong gas exchange. They like clean, oxygen-rich water, but not a sandstorm.
• Lighting: subdued. Give them shaded areas so they feel comfortable being out.

I set these up more like a public-aquarium style fish system than a reef. Big skimmer, oversized mechanical filtration you can actually clean easily, and lots of biological capacity. You also want a tight lid because sharks can and will surprise you, especially at night.

• Temperature: cool marine range (aim stable and on the cooler side).
• Salinity: standard marine (around 1.025-1.026), steady.
• Nitrate: keep it low. Sharks tolerate less "grunge" than people assume.
• Metals: avoid copper anywhere near the system. No copper meds, no mystery plumbing parts.

What to feed them

They are scent-driven predators. If you drop random pellets in the water column, they may ignore it completely. Target feeding works best: tongs, a feeding stick, or placing food right in their path once they are conditioned.

• Staples: marine-origin meaty foods like squid, shrimp, prawn, scallop, and chunks of marine fish.
• Whole seafood items: occasional pieces with skin/bone can help with texture and enrichment (not as the only diet).
• Variety: rotate foods so you are not feeding only one thing for months.

Portion control matters. Overfeeding a shark is easy and you pay for it twice: the shark gets fatty and the water quality tanks. I like smaller meals more often at first, then settle into a steady routine once the animal is eating confidently.

How they behave and who they get along with

Blotched catsharks are generally calm and spend a lot of time on the bottom, but they are still predators. Anything small enough to fit in their mouth is food eventually, especially at night. They also get stressed by constant harassment from big, pushy fish.

• Good tankmates: peaceful, cool-water compatible fish that ignore the shark and are too large to be eaten.
• Avoid: fin nippers, aggressive triggers, large wrasses that pick, and anything that likes to "test bite".
• Also avoid: small fish and crustaceans you want to keep. Shrimp and crabs are usually expensive snacks.

They are surprisingly easy to spook with sudden movement or bright light flips. Once they feel safe, they become pretty steady and you will see more natural cruising behavior instead of just wedging into a corner.

Breeding tips

Breeding this species in home aquariums is uncommon. Most catsharks lay eggs (the classic "mermaid's purse" cases), but getting consistent pairing behavior and viable eggs usually takes a large system, mature animals, and long-term stability.

• If you ever see egg cases: protect them from tankmates and high flow that can tumble them.
• Incubation: steady, cool temperature and high oxygen are your friends.
• Newborns: tiny, secretive, and prone to getting outcompeted or sucked into overflows if you are not careful.

Common problems to watch for

Most issues people run into are either temperature related, water quality related, or injury related. Sharks do not forgive sloppy systems, and they do not heal well if they are constantly being scraped up by rock or rough substrate.

• Heat stress: lethargy, rapid breathing, refusing food, hanging in high flow. Fix the temperature first, then look for other causes.
• Nose and fin abrasions: from rough sand, sharp rock, or cramped turns. These can turn into infections.
• Poor appetite: often from stress, bright lighting, harassment, or unstable parameters. Sometimes a food swap and quieter setup fixes it.
• Bloat or regurgitation: usually overfeeding, too-large chunks, or gulping food during a feeding frenzy.
• Parasites and "white spot": treat in a separate system and avoid copper-based approaches for the shark.

The best thing you can do is build the system around stability and easy maintenance. If you dread cleaning the filters, it will slip, and this species is not forgiving of that kind of slow decline.