Ghost 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

Scavenger that eats anything organic: fish food, algae, biofilm, decaying plant matter, dead fish, dead shrimp. In a community tank, they clean up whatever settles on the bottom. Supplemental feeding with sinking pellets, algae wafers, blanched vegetables (zucchini, spinach), and occasional frozen food keeps them healthy. They're not effective algae cleaners despite the marketing; their algae consumption is modest compared to Amano shrimp or nerite snails. Feed every other day if the tank has other food sources. In dedicated shrimp tanks, feed a small amount of shrimp food or blanched vegetable 2-3 times weekly.

Compatibility

• The cheapest and most expendable freshwater shrimp in the hobby. Sold for pennies as feeder shrimp and as 'algae cleaners.' The low price means they're frequently impulse purchases with little research.
• Safe with small peaceful fish. Any fish large enough to eat them will. Angelfish, cichlids, and most fish over 8 cm treat ghost shrimp as food, which is their intended purpose in the feeder trade.
• Can be aggressive toward smaller shrimp species. Ghost shrimp (Palaemonetes paludosus and related species) are larger and more assertive than cherry shrimp or Amano shrimp. They'll harass and occasionally kill smaller Neocaridina in shared tanks.
• Useful as live food for predatory fish. Their low cost and availability make them the standard feeder shrimp in the hobby.

Origin and habitat

Palaemonetes paludosus is a small freshwater shrimp native to the coastal plain of the eastern United States, from Florida north to New Jersey, living in ponds, lakes, and slow streams. It has also been introduced and established well outside that range, including the lower Colorado River in California and waters in Louisiana, Texas, and Oklahoma. Lewis Gibbes described it in 1850, originally as Hippolyte paludosa, and current taxonomy moves it into the genus Palaemon, so Palaemon paludosus is the accepted combination while Palaemonetes paludosus stays in wide use. The body is nearly transparent, marked with a fine pepper-dot speckling that helps separate the true species from look-alikes. True P. paludosus tops out near 2.5 cm, though shrimp sold as ghost shrimp are often larger because the trade name gets applied loosely. That loose labelling is the species' biggest identification headache: whisker shrimp in the genus Macrobrachium, with longer arms and bigger claws, no pepper speckling, and a more aggressive streak, are regularly sold as ghost shrimp. A so-called ghost shrimp that attacks its tankmates is usually a Macrobrachium rather than a Palaemonetes.

Breeding

Unlike some of its coastal relatives that need brackish water to raise young, P. paludosus breeds entirely in fresh water. Females carry a clutch of eggs under the abdomen, and at warm temperatures around 26 to 28 C the eggs hatch after roughly two weeks. The larval stage is brief, with larvae becoming post-larval shrimp within about a week and reaching maturity in two to three months in warm water. Because the ghost shrimp label covers several species in the trade, breeding results vary: an animal that is actually a brackish-larvae species will give berried females but no surviving young in a freshwater tank. Clutches are smaller and larval losses higher than with Neocaridina, so colonies build slowly even when the larvae do survive.

Common problems

A short life is the main limitation; these shrimp generally live only about a year to a year and a half, well under the span of cherry or Amano shrimp. They are also less tough than their feeder-animal price suggests. Sold cheaply and often held in crowded, unheated store tanks, many are already stressed and die within days of going home, so it helps to buy from a shop that keeps them in decent conditions. Like all shrimp they need enough dissolved minerals to molt cleanly, so hardness should not fall too low, and they are highly sensitive to copper, which rules out copper-based medications. Their willingness to catch and kill smaller shrimp, especially freshly molted Neocaridina, also surprises keepers who expect every shrimp to be peaceful.

Bioload

Further reading

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