• Species: Caridina gracilirostris

  • Species: Caridina breviata

  • Species: Caridina Cantonensis

  • Species: Red Cherry Shrimp

  • Species: Atya gabonensis

  • Species: Atyopsis moluccensis

  • Species: Caridina japonica

Shrimps

12 September 2017


Freshwater shrimps comes in a wide range of sizes and varieties, including a number of artificially-bred forms that only exist in captivity. While there are some quite large and predatory species out there, most of the shrimps traded fall into two categories: the very small 'algae shrimps' and the slightly larger filter-feeding 'fan shrimps'. Both sorts are popular, and may indeed be kept together, but their husbandry requirements are different, and that needs to be considered before purchase. The fan shrimps especially are fairly demanding animals that require specific types of food to do well.

Fan Shrimps

These shrimps come from tropical Africa and Asia and get their common name from their front legs which are adapted to form two pairs of fan-like structures used to capture plankton from the water. While they can consume food they find on the substrate, just like any other shrimp, they appreciate being filter-fed from time to time using the sorts of foods used by marine aquarists to feed corals and clams. Such foods can be directed at them using a turkey baster once or twice a week.

Besides special feeding, fan shrimps need an aquarium with a brisk current and lots of oxygen. If you can provide that though, you'll find these shrimps make excellent additions to community tanks when kept alongside small, inoffensive fish. They are peaceful, active during the daytime (usually lurking somewhere with a strong water current) and basically hardy. Like all shrimps though they are sensitive to poor water quality, so must be kept in a mature, well-maintained aquarium. Furthermore, medications that contain copper and formalin, such as those used to treat Whitespot, will kill them quickly. Fan shrimps are distinctly territorial though, and while you can keep groups without problems, you should ensure they have plenty of space to spread out, including numerous 'perches' they can use while filter feeding.

The Southeast Asian Common Rock Shrimp, Atyopsis moluccensis, is a regular sight in the better aquarium stores. It is mottled reddish-brown in colour with small off-white to yellowy spots on its flanks and an off-white band running along the back from nose to tail. Maximum length is about 10 cm. A well-maintained aquarium with plenty of water current is required, and tankmates need to be varieties that won't peck at these shrimps, particularly when they're moulting. Good companions include the smaller danios and minnows, guppies, x-ray tetras, penguin tetras and so on. They also coexist well with the algae shrimps having similar environmental requirements but different feeding preferences. Common Rock Shrimps are available at a number of stores including Maidenhead Aquatics at Lincoln, The WaterZoo in Peterborough, and Wildwoods in Enfield, who can also supply these shrimps by mail order.

Closely related to the Common Rock Shrimp is the Bamboo Shrimp, Atyopsis spinipes, also from Southeast Asia. Like other fan shrimps it varies its colouration with mood and environment, but in good conditions these shrimps are reddish-brown with numerous off-white squiggles running along their flanks and a distinctive off-white band along the back. Maximum length is around 8-10 cm, and basic care is identical to that of the Common Rock Shrimp. Bamboo Shrimps are fairly regularly traded, though often confused with Common Rock Shrimps by retailers and hobbyists alike. Nonetheless, at the time of writing at least two stores have them in stock, Pond Life Aquatics in Mill Hill and the Aquatic Design Centre in Central London.

Atya gabonensis is known by a number of names including Armoured Shrimp and Vampire Shrimp but these common names are very misleading! Like all fan shrimps this big (to 15 cm) West African species is a completely inoffensive species that needs to be kept in a quiet, well-maintained aquarium alongside only the most peaceful tankmates. It is rather an impressive animal though, it's large size and grey-blue colour make it look rather fierce and groups of them are definitely eye-catching! Like other fan shrimps they like to congregate near the filter outlet, but their larger size does mean that their territorial interactions tend to be a bit rougher, so take care not to overcrowd them. Atya gabonensis is less often seen in aquarium shops than the other fan shrimps but several shops have them in stock at the moment, including Maidenhead Aquatics at Oxford, Abacus Aquatics in Sidcup, and Wildwoods in Enfield, who can also supply these shrimps by mail order.

Algae Shrimps

The shrimps we call 'algae shrimps' are predominantly Caridina and Neocaridina species from East Asia. Although some are arguably subtropical or even warm temperate zone species, they all seem to do well in tropical aquaria provided the water isn't too warm (22-25 C is ideal) and the water quality is good. Plenty of water current and oxygen are important as well. They are not fussy about food, and unlike fan shrimps they can largely be left to forage for algae and scraps of leftover fish food. Indeed, standard algae wafers and flakes make excellent foods for them, though shrimp-specific foods enriched with micronutrients such as iodine are marketed that can help with the more demanding species. As their common name suggests, algae shrimps pick away at algae, and for this reason are particularly popular additions to nano planted aquaria. Their demands for space are minimal, and the smaller species will do well even in 'desktop' nano tanks that hold just a few litres of water.

Unlike fan shrimps, algae shrimps are highly sociable so should be kept in groups of at least six specimens. In the right conditions some species will breed readily, skipping the planktonic stage and instead producing well-formed juveniles able to fend for themselves. Algae shrimps should not be kept with larger tankmates, and many aquarists prefer to keep them on their own in set-ups tailored to their needs. However, the larger algae shrimps will do okay alongside 'nano' fish of similar size and personality, such as Dwarf Mosquitofish, Dwarf Rasboras and Ricefish.

Probably the best algae shrimp for beginners is the Cherry Shrimp, usually referred to as Neocaridina denticulata sinensis or Neocaridina heteropoda in the aquarium literature, though some experts believe Neocaridina davidi is in fact its correct Latin name. In any event, this shrimp is immediately recognisable and unlikely to be confused with anything else. Females are cherry red and get to around 3 cm or so in length; males are a little smaller, and mostly transparent with red squiggles and spots on their bodies. Besides the standard red form, blue, grey, orange, and green colour morphs are available, among others. Groups will breed readily in quiet, well-planted tanks, resulting in a colony of animals that have a lifespan of 1-2 years. Because they are colourful, hardy and easy to breed, Cherry Shrimps are regularly traded and inexpensive. At the time of writing several shops have them in stock, including Amwell Aquatics at Soham, Maidenhead Aquatics at Lincoln, Wholesale Tropicals in Bethnal Green, London, and Wildwoods in Enfield, who can also supply these shrimps by mail order.

Caridina japonica is widely known as the Amano Shrimp after the famous Japanese aquarist who popularised this species as an algae-eater for his elegantly planted aquaria. Unlike the Cherry Shrimp, Amano Shrimps have a planktonic larval stage and will not breed in captivity, but they do get a bit bigger (up to 5 cm) and live rather longer, 2-3 years being typical. They are basically transparent though a few spots of reddish-brown can be seen on their flanks. Native to Japan they can do well in both tropical and unheated aquaria, and if kept in substantial numbers they will do a good job of eating leftover food and picking away at algae without damaging even the most delicate plant species. This classic species is regularly traded and rightly popular among advanced aquarists, it's slightly larger than average size making it a better choice for quiet community tanks alongside small tetras, minnows and livebearers. Among the stores with this species in stock are Abacus Aquatics in Sidcup, Maidenhead Aquatics at Crowland, World of Water at Romsey, and Wildwoods in Enfield, who can also supply these shrimps by mail order.

The Red Rhinoceros Shrimp, Caridina gracilirostris, is a rarely-seen brackish water shrimp from South and Eastern Asia noted for its transparent body and the red tip to its nose-like rostrum. They are quite thin but long, getting to 3-4 cm in length, females being noticeably bigger than males. However, while they will survive for many months in very hard freshwater, they do need brackish water conditions to survive in the long term. They are unlike the other algae shrimps in another way too, being active midwater swimmers by choice, so an aquarium with swimming space and a gentle but steady current is what they prefer. While definitely a species for the advanced aquarist given their specific environmental needs, in a brackish water aquarium these shrimps aren't at all delicate, and breeding, though difficult, can be done by exposing the larvae to successively more saline conditions up to full seawater. The Red Rhinoceros Shrimp is not often traded, though at the time of writing is available at Maidenhead Aquatics at Crowland and World of Water at Manchester.

The Crystal Shrimp, Caridina cantonensis, is a small East Asian species noted for the alternating pattern of thick red and white bands seen on their bodies. Although very small, 2 cm or so when fully grown, the species isn't difficult to maintain though its small size precludes combining it with fish. They are also a bit more demanding in terms of water quality and do best in water that isn't too hard. On the other hand, it's a great favourite for aquarists setting up 'nano' planted systems containing just a few litres of water. It is breedable, the juveniles being essentially miniature versions of the adults. Maintenance is similar to that of other algae shrimp, but because different Caridina species will interbreed it isn't a good idea to mix them. Crystal Shrimps are not as commonly traded as some of the other shrimps discussed in this article, but the Aquatic Design Centre in Central London regularly has them in stock.

Bumblebee Shrimps, Caridina breviata, are similar to Crystal Shrimps in size and appearance except that they have blackish-brown and off-white stripes rather than red and white stripes, hence the 'bumblebee' part of their common name. They are excellent additions to 'nano' planted tanks, but again, their small size (barely 2 cm) largely precludes them from life alongside community fish, though some success has been had keeping them with exceptionally gentle micro-predators such as Indostomus spp. In any event, they do best in water that is moderately soft and has an around-neutral pH and will not tolerate poor water quality for any length of time. Rarely traded, but currently in stock at World of Water at Manchester.