Black redhorse

Where they come from

Black redhorse are North American suckers from the Great Lakes and Mississippi River drainage. Think cool rivers with steady current, gravel and cobble bottoms, and lots of drifting insect life. They are built for cruising and picking food off the bottom, not sitting in a glass box doing nothing.

Setting up their tank

This is an expert fish mostly because of space and water movement. A young one will use every inch you give it, and adults are big, powerful swimmers. If you are thinking standard 55-gallon, skip it. You will just watch it bang its nose and slowly lose weight.

• Tank size: I would not keep one long-term in under 180 gallons, and bigger is honestly better. Length matters more than height.
• Footprint: long and wide, like a river run. Stock tanks and big custom builds work great.
• Flow: strong. Use big canisters or sump, plus powerheads to create a directional current.
• Oxygen: high. Agitation and flow do more than extra gadgets.
• Substrate: smooth gravel, rounded river rock, and sand patches. Avoid sharp gravel - they spend a lot of time nosing around.
• Decor: keep the middle open. Pile rocks to make breaks in the current and a few calm spots.
• Lighting: moderate. They do not need bright reef-style lighting, but you want enough to grow a little algae and biofilm on rocks.

Water numbers are the easy part compared to habitat. Neutral to slightly basic is fine, and they appreciate it on the cooler side. What really makes them look good is clean water with low nitrate and lots of dissolved oxygen. If your tank ever smells "fishy," you are already behind.

What to feed them

Black redhorse are bottom foragers. In the wild they eat insect larvae, small crustaceans, snails, and whatever they can vacuum off the substrate. In a tank, the big challenge is getting steady calories into them without turning the tank into a nutrient soup.

• Staples: sinking carnivore pellets, high-quality bottom-feeder wafers, and gel foods that sink.
• Frozen: bloodworms, mysis, brine shrimp, chopped krill, and especially blackworms if you can get them.
• Fresh/live treats: earthworms (rinsed), live blackworms, small snails, and occasional river shrimp if you culture them.
• Plant matter: not a vegetarian, but they will pick at algae and biofilm. That is a bonus, not the diet.

I aim for smaller meals more often rather than one huge dump. They graze. If you only feed once a day, make it count and make it sink fast so tankmates do not steal everything.

How they behave and who they get along with

Temperament-wise they are peaceful, but they are not delicate. They are strong, fast, and always on the move. Most issues people have are not aggression problems - they are "wrong tankmates" problems (food competition, stress from crowding, or fish that cannot handle the flow).

• Good tankmates: other cool-water river fish that like current, like darters, larger shiners/minnows, some dace, and similar-sized suckers if the tank is huge.
• Use caution: small fish that sleep on the bottom (they can get bullied off food), slow fish, long-finned fish, and warmwater species that hate high flow.
• Avoid: nippy fish (they have big fins that get shredded), anything that needs calm water, and tiny fish you cannot afford to lose during feeding frenzies.

Expect a lot of cruising, nosing, and occasional bursts of speed. Give them clear runways. If you see pacing, glass surfing, or constant startle reactions, your setup is probably too small or too still.

Breeding tips

Breeding black redhorse in home aquariums is rare. In nature they spawn in spring over clean gravel in flowing water, often in groups. The triggers are seasonal: rising day length, temperature swings, and big water movement.

• If you want to try: think pond or very large indoor river system, not a living room aquarium.
• Simulate spring: cool winter period, then gradual warming and heavier feeding.
• Big current over gravel: they need a place where eggs will fall into crevices and not get eaten instantly.
• Expect egg predation: adults and tankmates will snack on eggs if given a chance.

Common problems to watch for

• Weight loss and "pinched belly": usually not enough sinking food, too much competition, or stress from cramped space.
• Damaged mouth or snout: often from sharp substrate, rough decor, or panic dashes in small tanks.
• Parasites from wild fish: flukes, ich, and internal worms are common. Quarantine and treat based on symptoms, not guesswork.
• Low oxygen stress: gulping at the surface, lethargy, hanging in the highest-flow area constantly. Fix flow and surface agitation first.
• Nitrate creep: they are messy eaters and big-bodied fish. If nitrates climb, you will see dull color and sluggishness.

If you do the big-tank, big-flow, clean-water thing and keep food on the bottom, they are actually pretty hardy. Most failures come from treating them like a generic community fish instead of a river athlete with a serious metabolism.