Tarebia granifera, common name (in the aquarium industry) the quilted melania,[1] is a species of freshwater snail with an operculum, an aquatic gastropod mollusk in the family Thiaridae.

[1] The indigenous distribution of this species includes the general area of these countries: India, Sri Lanka, Philippines, Hawaii, southern Japan, Society Islands,[6] Taiwan,[7] Hong Kong,[8] Thailand.

[1] Asia: In the South Africa, the snail has colonized different types of habitat, from rivers, lakes and irrigation canals to concrete lined reservoirs and ornamental ponds.

[1] It reaches very high densities, up to 21 000 m2, and is likely to impact on the entire indigenous benthos of the natural waterbodies of the region – more so than any other invasive freshwater invertebrate known from the South Africa.

[1] Prominent among these is the dense population (±6038 m2) found at a salinity of 9.98‰ (28.5% sea water) in Catalina Bay, Lake St Lucia, iSimangaliso Wetland Park, KwaZulu-Natal.

[1] From observations in Puerto Rico it was suggested that snails could survive temporarily saline conditions for several weeks by burying themselves in the substratum, emerging when fresh water returned.

[6] It is probable that dispersal of Tarebia granifera from one waterbody or river catchment to another occurs passively via birds, notably waterfowl, which eat them and void them later, perhaps in another habitat.

[1] Evidence for this comes from the finding of many small Tarebia granifera 5–7 mm in height and still containing the soft parts in unidentified bird droppings from the bank of the Mhlali River, South Africa.

[1] In the Nseleni River juvenile Tarebia granifera were commonly found with another invasive snail, Pseudosuccinea columella, on floating clumps of water hyacinth Eichhornia crassipes which provide a vehicle for rapid downstream dispersal.

[1] Once established in a particular waterbody Tarebia granifera is likely to disperse actively, both up and downstream in the case of flowing systems, as far as environmental factors like current speed and food availability will allow.

[1] The snail's tolerance of turbulent, flowing water was demonstrated by Prentice (1983)[16] who reported it migrating upstream on the Caribbean island of Saint Lucia at a rate of 100 m month−1 in streams discharging up to 50 L.s−1.

[1] In KwaZulu-Natal it has been collected in water flowing at up to 1.2 m.s−1 which is likely to exceed the current speeds of at least the lower and middle reaches of many rivers and streams in South Africa making these watercourses open to colonization.

[1] The sole of Tarebia granifera is proportionally small when compared to other thiarids and smaller snails with their higher coefficients were less able to grip the substratum in the face of moving water and so did not disperse as effectively as larger ones.

[1] Despite the very high densities recorded in the Nseleni River, indigenous invertebrates were still present in the sediments including:[1] bivalve Chambardia wahlbergi, chironomids, oligochaetes (tubificids) and burrowing polychaetes were also found but in very low numbers.

[1] Recent surveys by Vázquez et al. (2010)[14] of Pinar del Río Province, Cuba have reported population densities of Tarebia granifera of 85 individuals/m2, well above those of its endemic relatives (5 individuals/m2).

[1] Attainment of sexual maturity in Tarebia granifera is generally indicated by the size of the smallest snail observed to give birth rather than a histological assessment of the development of the gonad and associated reproductive structures.

[1] This suggests that differentiation of germinal cells in the ovary and their subsequent arrival in the brood pouch as blastulae is not a continuous process over a breeding season but occurs as one or more 'cohorts' or 'pulses' which stop before the birth rate of young snails reaches its maximum.

[1] Amongst these are several species of the family Heterophyidae some of which have been reported as opportunistic infections in people,[1][26] and another, Centrocestus formosanus (Nishigori, 1924), is an important gill parasite of fish.

[1] Tarebia granifera also serves as intermediate host for the philopthalmid eyefluke Philopthalmus gralli Mathis & Ledger, 1910 which has recently (2005) been reported affecting ostriches Struthio camelus on farms in Zimbabwe.

indigenous benthic gastropod species from rivers in Puerto Rico and have displaced the vegetation-associated pulmonate Biomphalaria glabrata from streams and ponds on several Caribbean islands.

[1] Anecdotal reports and observations suggest that in KwaZulu-Natal the indigenous thiarid Melanoides tuberculata is becoming less common and pressure from the spread of Tarebia granifera, particularly at high densities, is a possible explanation.