How to Identify Ocellated Flounder

To identify Ocellated Flounder (Bothus ocellatus), look at these key features.

Physical Characteristics

Body shape

flat

Coloration

Highly variable, adapting to the substrate. Typically mottled brown, tan, gray, or whitish with irregular spots, blotches, and rings (ocelli). Often has two prominent dark ocelli on the lateral line, one anterior and one posterior. The blind side is typically whitish.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Dextral (right-eyed) flatfish, meaning both eyes are on the right side of the head., Highly developed camouflage abilities, allowing rapid color and pattern changes., Males possess a prominent, forward-pointing spine on the snout (rostral spine) and often have elongated pectoral fin rays., Two distinct dark ocelli (eye-like spots) on the lateral line, though their prominence can vary.

Dorsal fin

Originates anterior to the eyes, with 84-96 rays. Continuous along the dorsal margin.

Tail fin

Rounded to slightly pointed, separate from dorsal and anal fins.

Pectoral fin

Well-developed; in males, the upper rays of the ocular-side pectoral fin can be significantly elongated.

Distinctive fins

Pelvic fins are small and asymmetrical, with the ocular-side pelvic fin having a longer base.

Identification Tips

1. 1

   Eye Position

   Both eyes are located on the right side of the head (dextral). This distinguishes it from sinistral (left-eyed) flounders.

2. 2

   Coloration and Pattern

   Observe the highly variable mottled pattern and the presence of two distinct, dark ocelli (eye-like spots) along the lateral line. These ocelli are often ringed with lighter coloration.

3. 3

   Rostral Spine (Males)

   Look for a prominent, forward-pointing spine on the snout of mature males. This is a key sexual dimorphic feature.

4. 4

   Pectoral Fin Length (Males)

   In mature males, the upper rays of the ocular-side pectoral fin are noticeably elongated, often extending beyond the caudal fin base.

5. 5

   Lateral Line

   The lateral line is strongly arched above the pectoral fin.

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