The Indo Pacific Tarpon, Megalops cyprinoides, has recently arrived in some UK shops. As Matt Clarke explains it isn't really suited to life in an aquarium...
Common name: Indo Pacific Tarpon
Scientific name: Megalops cyprinoides
Origin: Found in marine, brackish and freshwater from the Red Sea to Africa, India, Madagascar, Taiwan, Japan and Australia. Juveniles of this species are found quite far inland in freshwater (including the Shire River, a tributary to Lake Malawi) but the species is said to breed at sea.
Size: Ridiculously large at up to 150cm/60" and around 18kg. Tarpon are a popular big game fish in the tropics.
Diet: Primarily a piscivore - hence the enormous mouth. Stomach analyses have shown that they also consume crustaceans, such as shrimps, and terrestrial insects. They're not particularly fussy feeders in the aquarium.
Notes: Tarpon are members of the Megalopidae family and are in the Elopiformes order. Since they're often found in swampy areas, these fish have evolved an auxilliary air breathing organ and may gulp air from the surface. They can also tolerate very high salinities.
Aquarium: Due to its size, this species is not recommended as an aquarium fish, unless you have a public aquarium or indoor pool at your disposal. Although it's probably unlikely to grow much over a metre in captivity, as a rough guide, you'll still need a minimum tank of around 7 x 2 x 2m/23' x 6'6" x 6'6" to ensure this fish has sufficient room. Obviously, you'll also need to have an enormous filtration system and be skilled in keeping very large fish in the aquarium. Best avoided.
Identification: There are only two species of Megalops: cyprinoides and atlanticus. M. cyprinoides has 16-21 branched dorsal rays, 23-31 branched anal rays and nine or more pelvic rays. M. atlanticus has 22-25 branched anal rays, 13-16 branched dorsal rays and 37-42 scales in the lateral line series.
Availability: Fortunately, these are quite rare in the shops. However, we've seen half a dozen specimens at various shops on recent Shoptours, suggesting that one of the wholesalers is bringing these in. Some stores may be unaware of their potential size.
Price: Around £25 each.