Striped chub

Where they come from

Striped chub (Squalius kottelati) are a river fish from Turkey, tied to cool, fast, oxygen-rich water. Think clear runs, gravel, and current, not weedy ponds. That background pretty much explains why they are an expert-level fish in the average home aquarium.

Setting up their tank

Give them length and flow. I would not bother under a 4-foot tank, and bigger is better because these fish like to cruise. They get stressed and twitchy in cramped quarters, and stressed river fish are just a disease magnet.

• Tank size: aim for 75+ gallons (4-foot) as a starting point; 5-6 feet is even nicer
• Filtration: oversized canister or sump-style flow; you want turnover and oxygen, not a gentle trickle
• Flow: add a powerhead or river-manifold style flow if you can; they use it
• Temp: cool to mid range (roughly 16-22 C / 60-72 F); steady matters more than chasing a number
• Substrate: sand or rounded fine gravel; they will sift and nose around
• Decor: smooth stones, driftwood, and open lanes for swimming; skip delicate plants unless you protect them
• Cover: tight lid - spooked chubs can jump

The big trick is oxygen. High surface agitation and a lot of dissolved O2 makes them look "switched on" instead of lethargic. If the tank ever feels stuffy (film on the surface, fish hanging midwater with faster gill movement), you are already behind.

What to feed them

They are enthusiastic omnivores with a strong leaning toward whatever drifts by in a river: insects, small crustaceans, bits of plant matter, and the occasional fish egg or fry if they find it. In the tank, they do best on variety, not one "perfect" food.

• Base diet: quality sinking or slow-sinking pellets (they like to chase, but they also pick off the bottom)
• Frozen: bloodworms, daphnia, brine shrimp, mysis, chopped krill as an occasional treat
• Live (if you do it safely): blackworms, live daphnia - great for conditioning
• Veggie side: spirulina flakes/pellets, blanched spinach or zucchini now and then
• Feeding rhythm: smaller meals 1-2x/day; they stay cleaner and less bloaty than with big dumps of food

How they behave and who they get along with

These are schooling cyprinids with a pecking order. In a proper group, they spend more time cruising and less time picking on each other. Kept singly or in tiny numbers, the "boss" fish can turn into a jerk.

• Group size: 6+ is where their behavior starts to look normal; more is often better if the tank is big
• Temperament: generally not murderous, but they will harass weaker fish and outcompete shy eaters
• Best tankmates: other cool-water, current-loving species that can handle busy neighbors (sturdy dace/minnows, some loaches, certain barbs depending on temperature)
• Avoid: slow fancy fish, long fins, tiny nano fish, warm-water species, and anything that hates strong flow

Expect constant motion. They are not a "sit and watch the plants sway" fish. Also, they are fast at mealtime. If you keep them with anything slower, you will be target-feeding the slowpokes every single time.

Breeding tips

Breeding is doable, but it is not a casual weekend project. They are seasonal spawners in nature, usually responding to changing temps, longer days, and fresh, well-oxygenated water moving over gravel.

• Sexing: males are often slimmer and may show more breeding condition; females tend to be fuller when loaded with eggs (not always obvious)
• Conditioning: heavy feeding with live/frozen foods for a few weeks, plus big water changes
• Triggering: a gradual cool period then a slow warm-up, with strong flow and frequent cool water changes often helps
• Spawning site: clean rounded gravel or a riffle-style tray with flow across it
• Egg protection: assume adults will eat eggs; use a grate/marble layer or pull adults after spawning
• Raising fry: tiny live foods first (infusoria/rotifers), then baby brine shrimp as they grow

Common problems to watch for

Most issues I see with river cyprinids trace back to three things: not enough oxygen, too much heat, and not enough room. If you nail those, they are actually pretty hardy.

• Oxygen/flow stress: hanging near the surface, clamped fins, dull color - fix surface agitation and filtration first
• Heat stress: rapid breathing, listlessness, hiding - cool the tank and boost aeration
• Ich and other parasites: often show up after a new addition or temperature swing - quarantine new fish and avoid sudden changes
• Mouth/nose damage: they can scrape themselves on sharp rock while sparring or rushing the glass - keep hardscape smooth
• Bloat/constipation: usually from too much rich food and not enough roughage - cut back, add daphnia/veg, keep meals smaller
• Jumping: spooks during lights-on, maintenance, or chasing - lid gaps are how you lose them