The red-finned 'shark' with attitude — one per tank, no exceptions.
Rainbow Sharks (Epalzeorhynchos frenatum) are 6-8 inches (15-20 cm), dark-bodied with bright red fins, and like their red-tailed cousin they are territorial cyprinids, not true sharks. They are attractive algae-grazers but need careful social planning.
One per tank is the rule; they squabble with their own kind and with red-tailed sharks. Robust, fast tank mates and plenty of hiding places reduce conflict.
Rainbow Sharks live about 4-6 years with good care. Stable water and a solitary setup support that span.
What do Rainbow Sharks eat?
They are omnivores taking pellets, flake, algae wafers, and frozen/live foods. Overfeeding is the main diet error; they also graze on algae and biofilm.
Tank size and water parameters
A 50-gallon (190 L) tank suits a single fish. Target 72-79°F (22-26°C), pH 6.5-7.5, moderate hardness, zero ammonia and nitrite, nitrate under 20-30 ppm. Keep one per tank with caves and robust tank mates.
Common mistakes with Rainbow Sharks
Key errors: multiple sharks in one tank (constant fighting); red-tailed sharks as tank mates (they attack each other); too small a tank; and timid fish they harass.
Beginner mistakes to avoid
More than one shark — keep a single rainbow shark per tank.
Red-tailed sharks together — they attack each other.
Too small a tank — adults need 50+ gallons.
Timid tank mates — they bully peaceful fish.
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