Cherry Shrimp Enrichment: Surfaces to Graze, Not Food to Add

Shrimp are usually written about as decoration or as an algae solution. There is now a reasonable argument that they are neither.

What the Sentience Review Concluded

Birch, Burn, Schnell, Browning and Crump produced a review for LSE Consulting assessing the evidence for sentience in cephalopod molluscs and decapod crustaceans, published in 2021. They built an eight criterion framework and applied it to over 300 scientific publications.

The conclusion: cephalopods and decapod crustaceans are probably sentient. The UK government then extended the Animal Welfare (Sentience) Act to cover decapods, including shrimp, prawns, crabs, lobsters and crayfish.

The honest caveat, which the report itself makes: the case was weaker for some infraorders, penaeid shrimps among them, and the authors flagged the gaps instead of papering over them. Dwarf freshwater shrimp of the kind kept in aquariums were not where the strongest evidence sat. The general conclusion covers decapods as a group, and the specific evidence is uneven within it.

Surface Area, Which Is the Whole Thing

Nearly everything a cherry shrimp does is graze biofilm. That means the useful enrichment is not food, it is more square centimeters of grazeable surface.

Dense live planting, mosses especially, plus driftwood which grows biofilm readily and gives the colony a structure to work over. Add leaf litter, catappa or oak, which breaks down slowly into exactly what shrimp want to eat.

A tank of bare glass and gravel with a shrimp pellet dropped in is the impoverished version. A heavily planted tank with wood and leaves is a shrimp tank that mostly feeds itself.

Water Stability, Which Is the Welfare Item

More shrimp die from water than from anything else, and they are considerably more sensitive than the fish people compare them to.

Copper is lethal. Fish medications, some plant fertilizers and some tap water carry it, and a dose that a fish shrugs off can end a colony. Check everything that goes in the tank.

Swings matter more than values. Cherry shrimp tolerate a fairly wide parameter range and tolerate sudden changes badly. A water test kit and small regular changes beat large occasional ones.

A Colony, Not a Few

Cherry shrimp are visibly more active and more confident in numbers. A trio spends its life hidden in the moss; a colony grazes in the open.

Ten or more is a sensible start in a tank of reasonable size, and a healthy colony grows on its own. This is one of the few pets where the enrichment and the population manage themselves.

Molting, and the Minerals Behind It

Failed molts are a common cause of death and they are mostly a chemistry problem. Mineral content that is wrong or that swings suddenly is the usual cause.

Stable general hardness and a steady mineral supply do most of the work. Leave discarded shells in the tank. Shrimp eat them and recover the minerals. Our shrimp molting guide covers the process across invertebrates.

Cover, and a Safe Filter

Shrimp are vulnerable immediately after a molt and want somewhere to hide until the new shell hardens. Dense moss and leaf litter cover that.

Filter intakes need a sponge guard or a sponge filter, because shrimplets get drawn into unguarded intakes and that is a slow, invisible way to lose a colony.

Feeding, Sparingly

Once the tank is mature, most of the diet arrives on its own. Supplement lightly with a shrimp food or blanched vegetables, and remove what is not eaten.

Overfeeding is the standard mistake and it fouls water in a small tank quickly, which brings you straight back to the item that actually kills them.

Priority Order

1. Grazing surface: moss, plants, driftwood and leaf litter
2. Stable water, and nothing containing copper
3. A colony of ten or more
4. Stable minerals for molting, with old shells left in
5. Cover for freshly molted shrimp
6. A guarded filter intake
7. Light supplementary feeding, if any

What Not to Do

Do not put copper in the tank, in any form, including fish medication. Do not make large sudden water changes. Do not keep a bare tank with a food dish and call it a shrimp setup. Do not remove discarded shells. Do not run an unguarded filter intake. Do not overfeed. And take your time netting or moving them, since transfer shock kills more shrimp than the destination tank does.

A planted tank with wood and leaf litter is most of the enrichment plan.

Sources & Further Reading