Bamboo shrimp

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: any.

Behavior

Plant interaction: plant safe.

Typically wild-caught; acclimate slowly.

Feeding

Filter feeder. The shrimp parks itself in the current and holds its fan-shaped front legs (chelipeds covered in fine setae) open to catch microparticles, microalgae, organic detritus, and microorganisms drifting past, then sweeps the contents into its mouth. Food intake scales with the speed of the current, so they prefer fast flow. In an aquarium, supplemental food usually has to come in as a powder released upstream of the shrimp's perch (spirulina powder, finely crushed flake, baby shrimp food, pond plankton). Sinking pellets that work for grazing shrimp are not usable here. If a shrimp starts working the substrate with its fans closed, the water column is not providing enough food.

Compatibility

• A filter feeder, not a substrate scavenger. The shrimp perches on driftwood, rocks, or hardscape in the strongest part of the current and holds its fan-shaped front legs open to catch passing particles. Watching that behaviour is most of the reason people keep them
• Flow is essential. A tank with only mild filtration will not deliver enough suspended food to the fans, so a powerhead or a strong filter outlet pointed at the shrimp's preferred perch is functionally required
• Completely defenceless. Avoid large or aggressive species (cichlids, big barbs, puffers); the shrimp will be eaten or pushed off its spot
• Body colour shifts among brown, tan, reddish, and yellow-green depending on diet, mood, and where the animal is in its moult cycle. A red flush soon after a moult is normal, not a sign of illness
• Cannot be bred in a standard freshwater tank. Larvae need brackish to near-saltwater conditions while adults cannot, so essentially every bamboo shrimp on sale is wild-caught

Origin and habitat

A large filter-feeding atyid shrimp from the Indo-Pacific, described by De Haan in 1849 as Atyopsis moluccensis (family Atyidae). Naturally occurring populations are reported from Indonesia (the Moluccas give the species its name), Sri Lanka, Thailand, Malaysia, and probably the Philippines. The genus as a whole stretches across a much wider area, from Sri Lanka east to Samoa, north to Okinawa, and on the Asian mainland from the Malay Peninsula to India. The wild habitat is fast-running freshwater streams and rivers draining hill country, where the shrimp anchors itself on the underside of smooth boulders in the strongest part of the current and avoids the slower water near the banks. Atyopsis contains only two species; the other is A. spinipes, the dwarf bamboo shrimp, and the two are told apart by counting the small teeth along the underside of the rostrum (two to six in A. spinipes, seven to sixteen in A. moluccensis). The fan-shaped 'hands' that give the genus its appeal are actually the first two pairs of legs, modified into wide chelipeds covered in fine setae that filter out passing particles. The IUCN lists the species as Least Concern but flags the lack of population data; one 2004 publication, for instance, noted that A. moluccensis used to be common in the Gombak river in Malaysia and had become rare there, with the cause given as downstream urban development and pollution killing the larvae. Adults are typically 8 to 10 cm. Body colour ranges across brown, tan, reddish-brown, and a yellowish green, with thin reddish stripes along the sides and a paler line down the back; the colour often changes after a molt, and freshly moulted shrimp tend toward red. Captive breeding is not viable at any commercial scale and effectively all bamboo shrimp on sale are wild-caught, because the larvae need brackish or near-saltwater water to survive while the adult female cannot tolerate the salinity, so the larvae have to be moved into a separate setup almost immediately after hatching.

Breeding

Essentially not bred in the hobby. The life history is amphidromous: adults live in fresh water, but the larvae are planktonic and need brackish to near-marine water to develop, and the adult female cannot survive that salinity. A gravid female can carry a thousand or more very small eggs tucked under her pleopods. The few attempts that have worked involve mating the pair in fresh water, then catching the newly hatched larvae and moving them to a separate tank running 33 to 34 g of salt per litre (close to full seawater), raising them through their larval stages there, and gradually returning the survivors to fresh water. Another part of the difficulty is that this species only molts every couple of months, and mating happens right after a female moult, so even getting a berried female to start with is uncommon. Survival of the larvae is poor and the larval period itself is variable, so the species reaches the trade almost entirely through wild collection.

Common problems

If the shrimp stops using its fans in the current and starts picking at the substrate with the fans closed, the water column does not have enough suspended food for it. Fix it by increasing flow over its perch, adding fine powdered food (spirulina powder, finely crushed flake, baby shrimp food) upstream so the current carries the particles past the fans, or moving the shrimp closer to the filter outlet. Failed molts, where the animal gets stuck in the old shell, point at low calcium or unstable mineral levels; keep general hardness consistent and provide a calcium source. After a successful moult the new shell is soft for a few days and the shrimp will hide, which is normal. The species has no defence against predators or harassment, so anything large or aggressive (cichlids, big barbs, puffers) is a problem, and even harmless tankmates can disrupt feeding by knocking the shrimp off its favoured spot. Copper-based medications kill all shrimp.

Bioload

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size