How to Identify Siamese Algae Eater

To identify Siamese Algae Eater (Crossocheilus oblongus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

The body is silvery-brown to golden-brown dorsally, fading to a lighter, often whitish, ventral side. A prominent, irregular black horizontal stripe extends from the tip of the snout, through the eye, and along the lateral line to the caudal fin. The fins are typically clear or slightly dusky, lacking any red or yellow coloration.

Scale type

cycloid

Mouth position

subterminal

Distinctive features

Single prominent black horizontal stripe from snout to caudal fin., Absence of barbels on the upper jaw (or very small, inconspicuous ones)., Fins are clear, lacking red or yellow pigmentation., Mouth is subterminal with a rasping lower jaw for scraping algae., Can reach up to 6 inches (15 cm) in length, though often smaller in aquariums.

Dorsal fin

Single dorsal fin, typically with 8-9 branched rays.

Tail fin

Forked caudal fin, often with the black stripe extending into the lower lobe.

Pectoral fin

Paired pectoral fins, clear.

Distinctive fins

All fins are clear or slightly dusky, without any prominent coloration. The black stripe extends fully into the caudal peduncle and often slightly into the caudal fin lobes.

Identification Tips

1. 1

   Lateral Stripe

   The most reliable identifier is the distinct, jagged-edged black stripe that runs from the snout to the tip of the caudal fin. This stripe is usually solid and does not fade or become patchy.

2. 2

   Fin Coloration

   True Siamese Algae Eaters have clear or translucent fins, completely lacking any red, orange, or yellow pigmentation. This is a key differentiator from similar species like the Flying Fox (Epalzeorhynchos kalopterus).

3. 3

   Barbels

   Crossocheilus oblongus typically has only one pair of very small, often inconspicuous, maxillary barbels. Some individuals may appear to have none. This contrasts with Flying Foxes which have two prominent pairs of barbels.

4. 4

   Swimming Behavior

   SAEs often rest on plants or substrate using their pectoral fins, but they are also active swimmers, often hovering in the water column or grazing on surfaces. They do not typically 'perch' on fins like some other loaches or bottom dwellers.

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