Blue dream 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.

Feeding

Grazes more or less constantly on biofilm, algae, leaf litter, and decaying plant matter. In a mature, planted tank with established biofilm, a small colony will often need no supplemental food at all. When supplemental food is required (bare tanks, new setups, larger colonies), use shrimp-formulated pellets, blanched zucchini or spinach, or small amounts of a high-quality fish flake. Snowflake food (dried soy hulls) is widely used since it doesn't foul the water and feeds the colony slowly over a day or two. The single most important feeding rule: copper is toxic to Neocaridina at concentrations that don't affect fish. Check ingredient labels on food and especially on plant fertilizers and medications, since fish-safe copper levels can wipe out a shrimp colony. Overfeeding is the most common beginner mistake; in a planted tank, feeding two or three times a week is normally enough.

Compatibility

• Same species as cherry shrimp (Neocaridina davidi) selectively bred for blue colour, so all the same care rules apply. The blue is built up through generations of culling rather than a single dominant gene
• Mixing with any other Neocaridina colour line (cherries, yellows, oranges, greens, etc.) produces mixed-colour offspring that revert toward wild-type brown over a few generations. Single-colour tanks are the rule for keepers who want the line to hold
• Safe with anything that can't eat them. In practice, that means a species-only tank, or a tank with otocinclus and small snails. Even small tetras pick off shrimplets, so colony growth is best in fish-free tanks
• Hardy across a fairly wide range of conditions, but the blue colour shows best in harder, more alkaline water (pH around 7.0-7.5, GH 8-12). Soft acidic water tends to wash the colour out

Origin and habitat

A selectively-bred colour morph of the dwarf freshwater shrimp Neocaridina davidi, the same species that is sold as cherry shrimp, fire red, orange sakura, yellow neon, green jade, snow white, and a long list of other trade names. Bouvier described the wild species in 1904, initially placing it in Caridina; the genus Neocaridina was separated by Kubo in 1938, and the species has cycled through several names since (Neocaridina denticulata sinensis Kemp 1918, Neocaridina heteropoda Liang 2002, and others), all of which are now treated as synonyms of N. davidi. Native range covers Taiwan, eastern China, the Korean Peninsula, and Vietnam, where the wild form is a mottled brown shrimp camouflaged against leaf litter and submerged wood. Aquarium-trade releases have led to established invasive populations in thermally altered water in Japan, the United States, Poland, and Germany. Blue dream shrimp originated as one of several blue colour lines (alongside blue velvet, blue jelly, and blue diamond, all of which look similar but were stabilized from different starting stocks). The naming overlap in the trade is genuinely confusing; blue dream and blue velvet in particular are sometimes used interchangeably even though most serious breeders treat them as distinct lines. Grading runs from translucent, splotchy specimens at the low end to deeply opaque, fully-blue shrimp covering the legs and underside at the top. The shrimp itself is around 3 to 4 cm at maturity, lives one to two years, and reaches breeding size at roughly 30 days. All Neocaridina colour morphs interbreed freely, and a colony mixed with other colours reverts toward the wild-type mottled brown within three to five generations as the colour-modifier genes get diluted.

Breeding

Breeds without intervention given stable water and a mixed-sex group. A female ready to mate displays a 'saddle': a pale yellow, green, or olive crescent visible behind the head, which is the developing egg mass in the ovaries. After mating, the eggs move into a brood pouch under her abdomen (the 'berried' state). Clutch size is roughly 20 to 40 eggs depending on female size, and the female carries them under her pleopods for about 25 to 35 days, fanning them continuously to keep oxygen flowing and prevent fungus. There is no larval stage: shrimplets hatch as miniature versions of the adults and start grazing biofilm the same day. A healthy starter group of ten can grow into the low hundreds within six months given clean water, no predators, and reasonable feeding. The actual limits on colony growth are predation (any fish with a mouth wide enough will eat shrimplets and many will take adults), water quality (ammonia and nitrite kill quickly), and copper contamination. To keep the colony blue, the keeper has to cull off-colour shrimplets (browns, clears, or wild-type revertants) each generation; without that selective pressure the colony drifts back toward wild colouration within a few generations. Off-colour culls sell or trade well through local fish stores and shrimp groups.

Common problems

Almost every major Neocaridina problem traces back to molting and minerals. The shrimp grows by shedding its old exoskeleton, and if calcium, magnesium, or overall GH are off, the shrimp gets stuck mid-molt and dies. The textbook target is GH 6-12 dGH with KH 3-8, TDS around 150-250 ppm, and a steady calcium source from substrate, cuttlebone, or remineralised RO water. The other half of the equation is parameter stability: shrimp that have been kept at GH 14 for months are fine, but shrimp moved from GH 6 to GH 12 overnight will mass-die. Drip-acclimate new arrivals over an hour or more. The white band that sometimes appears around the midsection (often called 'white ring of death') is the visual sign of molting failure, and there is no treatment once it shows up; it indicates mineral imbalance or parameter shock. Copper wipes out colonies in trace amounts, so plant fertilisers and fish medications need to be screened. Hydra and planaria sometimes hitchhike in on plants and prey on shrimplets; fenbendazole handles planaria, manual removal works for hydra. Colour fading across generations is normal without ongoing selection: cull to maintain the line. Several epibiont species (Scutariella japonica, Holtodrilus truncatus, and some newer described Cladogonium and Monodiscus species) hitchhike in commercial shipments and can affect breeding rates, though they're not usually fatal.

Bioload

Further reading

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