Forty Gallons, Bought as Floor Area
The yoyo loach's tank size surprises people who meet it as a two-inch juvenile in a shop. Adults reach four to five inches, they are deep-bodied and active, and they are group fish: five or six together is the social unit to plan for. That adds up to a forty-gallon breeder tank as the minimum — chosen for its wide, shallow footprint rather than its height — and fifty-five gallons or more if the group shares with a community. A standard tall tank of similar volume gives loaches a cramped floor and forces their whole social life into too few hiding places.
A Social Fish With a Pecking Order
Yoyo loaches, named for the dark markings that can read like the letters Y-O-Y-O along a young fish's flanks, live in a loose hierarchy. In a proper group they wrestle harmlessly, chase in circles, rest piled against each other, and greet feeding time with clicking sounds and frantic whisker-work across the sand. Kept alone or as a pair, the same loach often turns shy by day and pushy toward other bottom fish by night. Numbers are the temperament fix: with five or six, the sparring stays inside the group and the tank's other residents are left in peace.
Caves, Sand, and Room to Dig
Build the floor around them: smooth sand or fine substrate they can sift without injuring their barbels, and at least as many caves, wood tangles, or tube hides as there are loaches, spread across the whole base so a subordinate fish can always break a line of sight. Yoyos famously wedge themselves into impossibly tight gaps and play dead on their sides while resting — before you panic over a motionless loach, watch for slow gill movement and give it a minute. Keep the lid tight and cover filter intakes, because an exploring loach will investigate any opening that promises a current.
Tank Mates and the Snail Question
Yoyos suit robust community fish that occupy the middle and top — larger tetras, rainbowfish, barbs in well-chosen species, and peaceful cichlids of modest size — and they generally leave upper-level fish alone. They are celebrated snail hunters, which is either the reason you bought them or a disaster for a prized snail collection, so decide which before they go in: ornamental snails will be eaten. Small, delicate shrimp are at risk from an adult loach's investigations too, while larger shrimp and armoured bottom companions usually fare better.
Growth, Feeding, and Long-Term Care
Feed yoyos as the omnivores they are: sinking pellets and wafers as the base, with frozen bloodworm-type foods, blanched vegetables, and other variety rotated through the week, delivered where the loaches gather rather than scattered for faster fish. A growing group produces real waste, so the bigger tank recommendation includes filtration and weekly partial water changes to match. Watch for a loach that stops joining the group's evening forage, or one losing weight while the others round out — bottom fish can be quietly outcompeted. A household log of feeding spots and which caves are occupied helps everyone read this group, and KinsLe Family Sharing keeps those details shared for the whole family.