Keeping Dwarf Shrimp with Fish: Predation, Companions and Cover

How fish size and mouth decide whether adult dwarf shrimp and shrimplets survive, which fish groups sources pair with Neocaridina and Caridina, and the cover that improves survival.

Fish eat any shrimp that fits in their mouths. Adult dwarf shrimp survive alongside small, peaceful fish, while newborn shrimp about 1 mm long are at risk from almost any fish. Algae-grazing Otocinclus and the tiny Boraras rasboras are the companions sources name most often. Dense planting and moss are what allow shrimplets to survive, and a shrimp-only tank raises the most young.

How predation depends on fish size and mouth

Tropical Fish Hobbyist states the rule directly: if the shrimp can fit into a fish's mouth, that fish is not a good tankmate. It also notes that baby shrimp tempt even the smallest fish. Wikipedia gives an adult size of about 3–4 cm for Neocaridina davidi. The young hatch as tiny copies of the adults, roughly 1 mm long, with no larval stage, from batches of 20–30 eggs that take 2–3 weeks to hatch. Caridina cantonensis also hatches as miniature adults. There are therefore two separate thresholds. A fish may leave adults alone and still eat every shrimplet. Practical Fishkeeping makes the same point: fish eat anything that fits in their mouths, and newborns are very vulnerable.

Fish groups and their reported risk

Lowest risk: Practical Fishkeeping describes Otocinclus and their relatives Parotocinclus and Hypoptopoma, including the zebra oto (Otocinclus cocama), as the safest option, even with newborn shrimp. These fish are algae grazers that show no interest in shrimp and often cannot eat them.
Dwarf rasboras (Boraras): Practical Fishkeeping notes their tiny mouths, and Seriously Fish states that Boraras brigittae can be kept with Caridina and Neocaridina shrimp in planted tanks.
Likely to eat young but may live with adults: guppies, rasboras, small danios, kuhli loaches, pencilfish, clown killifish, Corydoras, white cloud mountain minnows and small Pseudomugilidae rainbowfish. Practical Fishkeeping says these will almost certainly eat shrimplets, but adults may survive if the colony is allowed to build up before the fish are added.
A gamble: bettas and dwarf puffers. With bettas the outcome depends on the individual fish. Some ignore shrimp, while others wipe out a colony within days.
Unsuitable: all cichlids including angelfish and discus, goldfish, large rainbowfish, large gouramis, spiny eels, and the larger livebearers and loaches. In Practical Fishkeeping's words, it is not a matter of if but when these fish will eat shrimp.

Practical Fishkeeping's Neocaridina FAQ adds smaller Corydoras, small plecos, dwarf gouramis, small tetras, smaller Rasbora species, cherry barbs and kuhli loaches as possible companions, all on the condition that the tank is densely planted. Tropical Fish Hobbyist says small tetras, rasboras and other non-aggressive small fish should be fine with cherry shrimp. For the more delicate bee shrimp, it limits companions to the smallest fish, such as Otocinclus or the least killifish (Heterandria formosa), and advises a species tank for breeding.

Water parameters: Neocaridina, Caridina and their companions

Neocaridina davidi (cherry shrimp and colour forms): Practical Fishkeeping gives a tolerance of 18–28 °C, with the longest life and best breeding at 21–26 °C, and pH 6.5–8.0 in medium to hard water. Tropical Fish Hobbyist gives 70–80 °F (about 21–27 °C) and pH 6.5–8.0.
Caridina cantonensis (bee and crystal red shrimp): Wikipedia gives 21–26 °C, with the strongest colours at 24–25 °C, and soft water. Tropical Fish Hobbyist advises not exceeding about 74 °F (about 23 °C), with pH around 6.5, GH 4–6 and KH about 2.
Boraras brigittae: 20–28 °C, pH 4.0–7.0, 1–10 dGH (Seriously Fish).
Otocinclus cocama: 21–25 °C, pH 6.0–7.5, 2–10 dGH (Seriously Fish).

Soft, slightly acidic water at about 21–23 °C and pH around 6.5 suits both bee shrimp and Boraras. Cherry shrimp prefer harder water, and their overlap with Boraras is limited to about pH 6.5–7.0. The zebra oto's range covers part of the ideal range for both shrimp genera. Seriously Fish adds that it is timid, needs a group of six or more and abundant plants, and is suited to tanks with only small, non-aggressive companions.

Cover that improves survival

Moss and dense planting: Practical Fishkeeping's Neocaridina FAQ calls mosses and other places to hide and feed very important when shrimp share a tank with fish. Tropical Fish Hobbyist recommends live plants, moss and cholla wood as shelter for bee shrimp.
Time to establish: Practical Fishkeeping suggests letting the shrimp colony build up before adding fish.
Realistic expectations: in a community tank, Tropical Fish Hobbyist reports that a few shrimplets survive by hiding until they are too large to be in danger, and that a species tank raises the most shrimp.
Group size: Practical Fishkeeping keeps Neocaridina in groups of at least six, because they become shy in smaller numbers.

Shrimp with bettas are covered in more detail in the betta tank mates guide, and general stocking principles in the fish compatibility guide.