The Rainbow Shark (Epalzeorhynchos frenatum) is a long-time favourite in the aquarium hobby. This fish is not actually a shark at all, but is actually a cyprinid (minnow) that is known for its coloration and activity. It is a very active fish that spends most of its time grazing on algae, bio film, and other microorganisms in the aquarium. While it is somewhat gregarious as a juvenile, it becomes much more solitary as it reaches adulthood and can be territorial with its own kind as well as fish that are similar in appearance, such as Siamese Algae Eaters, Flying Foxes, and Garra species.
Care is simple for the Rainbow Shark. It is tolerant of a wide range of water parameters, but it will thrive in an aquarium with ample filtration and moderate to high water flow. This active fish is known to jump occasionally, so a secure aquarium lid is recommended. It will readily eat most high-quality dry foods rich in vegetable matter, but it should be offered fresh vegetables such as zucchini and cucumber as well. Live, frozen, and dry meaty foods are also essential for this omnivorous fish.
As stated above, the Rainbow Shark is a generally peaceful fish (although each specimen has its own personality), but it will prey on dwarf shrimp and other very small invertebrates. It does not seem to bother most larger snails, and we have found it to be generally peaceful with most larger shrimp (such as Amano, Flower, Green Lace, and Vampire Shrimp) as long as they are too large to be considered easy prey. The Rainbow Shark is a social fish as a juvenile, but can become more territorial with its own kind and similar-looking species as it matures. It must be kept in groups of at least 6 fish in a large tank to avoid harassment of subdominant specimens, or else it should be kept singly. Aggression can be kept to a minimum in a larger tank with plenty of territory and cover for each
What We Like About This Fish:
- Striking coloration
- Will not eat ornamental plants
- Generally peaceful disposition with fish and peaceful larger invertebrates
- Very active and noticeable fish in any aquarium
- Very hardy
RECOMMENDED TANK PARAMETERS:
Temperature: 68° - 79° F (20° - 26° C)
pH: 6.5 - 8.0, although the middle of this range is optimal
KH: 2 - 15 dKH
Minimum tank size: 55 gallons for a single adult
Diet: Omnivorous. Will easily accept high quality dry and frozen foods as well as fresh vegetables.
Social behaviour: Generally peaceful, schooling/shoaling as a juvenile. Can be territoral with its own kind or similar fish as an adult