Neocaridina — one species, every color

They all interbreed — and the offspring go brown

The color morphs sold as cherry, blue dream, yellow and the rest are selectively bred lines of one species, Neocaridina davidi. Put two colors in the same tank and they will breed with each other freely. The first generation may look passable. By the second and third, the recessive selection that produced those colors comes apart and you get wild-type shrimp: translucent brown-grey with a pale dorsal stripe.

This is not a defect and it is not something you did wrong. It is what happens when you undo decades of selective breeding in one tank.

The exception worth knowing: Neocaridina and Caridina are different genera and do not interbreed, so a Neocaridina tank and a Caridina tank can share a room without risk. They want quite different water, though, which is usually the reason to keep them separate anyway.

What they need

Here is the good news for anyone local: San Diego tap water is at the hard end of this range, and a little past it. The city’s 2025 report averages roughly GH 13, TDS 530–590 ppm and pH about 8.3. That is a nuisance for a lot of the hobby and workable for Neocaridina. Dechlorinate it and use it; cutting it with RO is optional if you want the deepest colour. You do not need a remineralizer, and you do not need to chase numbers. People who over-engineer a cherry shrimp tank tend to do worse than people who leave it alone.

The four things that actually kill them

1. Copper

Copper is lethal to invertebrates. It turns up in fish medications — especially ich and external parasite treatments — in some snail-control products, and occasionally in plant fertilizers at higher-than-label doses. Read every label before it goes in the tank. This rule has no exceptions and no safe margin.

2. Sudden changes in dissolved solids

Shrimp cope with a wide range of parameters and very poorly with rapid change in them. A large water change with water that has a different TDS, or a new bag of shrimp dumped straight in, causes osmotic shock. Keep water changes modest and frequent rather than large and occasional, and drip acclimate anything new over an hour or more.

3. Failed molts

Shrimp grow by shedding their shell. If GH is too low there is not enough calcium and magnesium to build the new one, and you find the shrimp dead, partly out of the old shell, often with a visible white band at the neck — the “white ring of death”. The fix is mineral content, not food.

4. Being eaten

Adult Neocaridina are about an inch. Shrimplets are two millimetres. Almost any fish with a mouth big enough will take the babies, including fish sold as peaceful — tetras, rasboras, guppies and bettas all count. A colony in a community tank does not usually die; it just never grows. If you want numbers, keep them in a species tank.

Feeding, and the thing people get backwards

Biofilm is the actual diet. Shrimp graze the invisible microbial layer on every surface all day long, and prepared food is a supplement to that rather than a meal plan. This is why a mature, planted, slightly untidy tank grows shrimp better than a spotless new one, and why shrimp added to a tank set up last week often thin out over the first month even though the water tests perfectly.

Feed a small amount every other day — a fraction of a pellet for a small colony — and remove anything not eaten within two hours. Overfeeding is the single most common cause of a colony crash, because uneaten food drives a bacterial bloom that strips oxygen. A fast day once a week does no harm at all.

Add botanicals. Catappa and magnolia leaves, alder cones and cholla wood all grow biofilm, release mild tannins and give shrimplets somewhere to graze out of reach. They are cheap and they do more for a colony than most bottled products.

Telling males from females

Females are larger, deeper in color, and develop a visibly curved underside as they mature. A female carrying unfertilised eggs shows a pale “saddle” on her back behind the head; a berried female carries the fertilised eggs under her tail and fans them constantly. Males are smaller, slimmer and noticeably paler — which is why a tank of all-males looks disappointing and a tank of all-females looks great and never breeds.

Eggs hatch in roughly three to four weeks as fully formed miniature shrimp. There is no larval stage, no brackish phase and nothing for you to do. This is the key practical difference from Amano shrimp, which cannot be bred at home.

Which color should you start with?

Buy ten or more to start. A colony needs enough founders to have both sexes and enough genetic spread to avoid a bottleneck, and shrimp are more confident — and far more visible — in numbers.

Questions we get asked

Can I keep cherry shrimp and blue dream shrimp together?

You can, but you should not. They are the same species and will interbreed, and within two or three generations the offspring revert to wild-type brown. Keep one Neocaridina color per tank.

Do I need RO water for Neocaridina in San Diego?

No. San Diego tap water is hard enough for Neocaridina, and a little harder than ideal. Dechlorinate it and use it; cutting it with RO is optional. RO plus remineralizer is only necessary for Caridina.

Why are my shrimp dying after water changes?

Almost always osmotic shock from a change in total dissolved solids, or chloramine that was not neutralised. San Diego water is chloraminated and will not gas off overnight, so it must be treated every time. Keep water changes small and frequent.

How many shrimp should I start with?

At least ten. That gives you both sexes and enough genetic diversity for a colony to establish, and shrimp behave far more naturally in a group.

Will my fish eat them?

Adults are usually safe with small, peaceful fish. Shrimplets are not safe with anything. If you want the colony to grow in numbers, keep them in a species-only tank.

Keep reading