A siamese algae eater kept alone often becomes a different fish from the one in the shop tank: bolder with tankmates, more territorial about a favourite leaf, and quicker to latch onto slow, flat-bodied fish. In a group of five or six, that energy turns inward — they chase each other briefly, graze side by side, and largely ignore everyone else. For most keepers, the group is the version of this fish worth having.
Why pairs and trios cause trouble
Two or three siamese algae eaters usually sort themselves into one boss and the rest being bossed. The lowest fish gets chased from food and resting spots, eats last, and stays thin while the dominant fish thickens. Five or six fish dilute that hierarchy until no single fish can police the whole tank. If your tank cannot hold five, a single fish in a peaceful community is a better plan than a stressed pair.
The tank a group actually needs
Adults reach roughly six inches and are strong, restless swimmers, so a group wants fifty gallons or more and a footprint with real length. They come from flowing rivers, and a current to swim against, plus broad leaves, smooth stones and driftwood to rest on, keeps them behaving naturally. A lid is not optional: startled siamese algae eaters jump, and they are most active at dawn and dusk when the room is quiet.
Feeding a working group
The famous appetite for black beard algae is real in young fish, but a group will not live on algae alone — and well-fed adults that discover flake and pellets can go off grazing. Feed sinking wafers and blanched vegetables after lights-out a few times a week so slower tankmates are not outcompeted, and let the group work the tank's algae in between. Resting on leaves with fins fanned, rather than constantly scouring, is normal daytime behaviour for a settled adult.
Making sure you bought the real fish
Several lookalikes share the shop label: flying foxes, false siamese algae eaters and Chinese algae eaters all wear a dark lateral stripe. A true siamese algae eater's black stripe runs unbroken into the tail fin, its fins are clear rather than black-edged, and it has one pair of small mouth barbels. Checking before you buy matters, because the Chinese algae eater grows into a fish that rasps the slime coat off its tankmates — the exact behaviour people wrongly blame on the true species.
Which algae they earn their keep on
Young siamese algae eaters are prized for tackling black beard algae and the soft hair algae most other fish ignore, but they will not shift hard green spot algae off the glass, and they cannot thrive on brush algae alone in a clean tank. Set the group's job description realistically — algae control support, not a cleaning service — and keep up your own glass scraping and water changes alongside their grazing, so the tank never depends on six hungry fish doing all of the work.
With several mouths to monitor, splitting the routine helps: KinsLe Care Teams lets you assign the evening wafer feeds and weekly water changes for the group to whoever is home, with each finished task marked off so nothing gets doubled or missed.