Siamese Algae Eater

About

A shoaling cyprinid from Malaysia and Sumatra, Crossocheilus langei is almost certainly the fish most commonly sold in the hobby under the names 'Siamese algae eater', 'Siamese flying fox', and 'Crossocheilus siamensis'. Though that last name is a taxonomic tangle that has caused decades of confusion. Telling this species apart from its near-identical relatives takes a careful eye: look for a reddish-golden iris above the pupil, two pairs of barbels, a straight lateral line running through the center of the dark body stripe, brownish fins, and a dark blotch on the underside just in front of the anal fin. During sparring bouts the body stripe fades but doesn't widen, which helps distinguish it from similar species. In the wild these fish form loose aggregations and that social structure carries over into the aquarium. Keep them in a group of six or more, since individuals kept in smaller numbers can become withdrawn or get picked on by dominant tankmates. They are generally compatible with other peaceful community fish, and pairing them with species from their native waters in Malaysia or Sumatra makes for a particularly natural-looking setup. Breeding in captivity has not been documented, and wild populations undertake seasonal migrations tied to water levels.