Feeding shrimp: what, how much, and how often

Shrimp that die in an established tank are more often sitting in the mess left by food nobody ate than going hungry, though that ranking is keeper impression rather than measured data. A mature planted tank already grows most of what a small colony runs on, so anything you add is a top-up rather than a meal. Offer an amount the colony clears in two to three hours, every second or third day, and take out whatever is left.

Biofilm is the staple, not the snack

Biofilm is the slippery layer of bacteria, single-celled algae, diatoms and their secretions coating every surface in a tank: glass, driftwood, leaves, filter sponge, substrate grains. Both Neocaridina davidi and the Caridina we keep (Caridina cantonensis, Caridina mariae) are grazers. Watch one for a minute and you will see it picking almost non-stop with the fine setal brushes (tiny bristles) on its first two pairs of legs. That grazing, not your feeding, supplies most of its nutrition.

So the tank matters more than the food does. Plenty of grazing surface, meaning mosses, driftwood, cholla wood, leaf litter and a mature sponge filter, gives you a colony that is rarely short of food. A bare tank has to be fed deliberately, and it punishes mistakes faster.

A new tank needs almost no food

This is the most common overfeeding trap. A tank cycled and left running for a few weeks carries a standing crop of biofilm and algae. Add ten or twenty juveniles and they cannot graze it down quickly, so there is little for prepared food to do except rot.

Meanwhile a young tank's biological filter has little spare capacity. Uneaten food breaks down into ammonia, and dwarf shrimp are generally considered more sensitive to it than the hardy fish most of us learned on. You are adding ammonia to the system least able to process it.

So feed nothing for the first week after the shrimp go in, then a single small crumb every third day. Still there next morning means feed less. Shrimp Zone ships unsexed juveniles (young, not yet sexable) at 0.6 to 1.2 cm, and animals that size eat very little. The Shrimp Care and Acclimation Guide covers the first few days.

What to feed on top of biofilm

Prepared shrimp foods

Choose one built around plant matter and algae rather than fishmeal. Copper is a question of dose rather than something to be purged. Shrimp require trace copper: haemocyanin, the copper-based protein that carries their oxygen, is built on it, and it also has a role in moulting. What kills them is a high dose, above all copper-based fish and snail medications and measurable free copper in the water column (the water itself). Keep those out of the tank, but do not try to strip the trace amounts out of a shrimp food or a plant fertiliser. Buy food formulated for shrimp.

Blanched vegetables

Cheap, useful and easy to overdo. Zucchini, spinach, kale, green beans, carrot and pumpkin all work. Boil a thin slice until it softens and sinks, a minute or two for leafy greens and longer for carrot or pumpkin, then cool it first. No salt, no butter, no oil. Wash produce well, since pesticide residue is a plausible risk to invertebrates at levels harmless to us.

Vegetables foul faster than dry food. Two to three hours is plenty. Some keepers leave zucchini in overnight with no trouble; others blame that for planaria (small flatworm pests) outbreaks, though planaria are scavengers and predators that respond mainly to protein-rich surplus rather than plant matter. In a young or lightly planted tank, take the short option.

Leaf litter and botanicals

Indian almond leaves (Terminalia catappa), mulberry and oak are slow-release grazing rather than a feed. They soften over weeks, grow biofilm, and give shrimplets (baby shrimp) cover. They also release tannins, which tint the water and can pull pH down where carbonate hardness is low, so add a couple at a time. Carbonate hardness works in two ways: it makes a pH swing less likely to happen at all, and when pH does move it reduces how far it moves. In a well-buffered tank the effect is usually small. Use only leaves you can identify as aquarium-safe, collect them well away from roadsides and sprayed gardens, and dry them fully. Many Australian natives, eucalyptus in particular, are high in oils and should not be substituted, and which natives are genuinely shrimp-safe is not well documented.

Powdered foods for shrimplets

Baby shrimp do not need targeted feeding in a mature tank; they graze the same biofilm as the adults. Powders earn their place in sparse or bare tanks, but they are the easiest product on the shelf to overdose. Whatever the dosing chart says, start at a fraction of it. They feed bacteria as much as shrimp, and a heavy dose in a small volume can drive a bacterial bloom that pulls dissolved oxygen down overnight, though the dose at which that happens is not well established.

Minerals and calcium are mostly a water job

Shrimp moult to grow, and a failed moult is often fatal. The calcium and magnesium used to build a new exoskeleton (outer shell) come mainly from the water column, measured as general hardness (GH). Food is a secondary source. KH — carbonate hardness — is the separate measure that steadies pH, and TDS is total dissolved solids.

Neocaridina do well around GH 6 to 10 dGH, KH 2 to 6 dKH, pH 6.8 to 7.8 and TDS 150 to 250 ppm, at roughly 20 to 24 °C. Sulawesi shrimp want a similar KH, 3 to 6 dKH, though their pH and GH sit well outside the Neocaridina figures above. Bee-type Caridina cantonensis want it softer and slightly cooler: GH 4 to 6 dGH, KH 0 to 1 dKH, pH 5.5 to 6.5 and TDS 100 to 150 ppm, at 20 to 24 °C. One recipe does not cover the genus, though: tiger shrimp (Caridina mariae) are usually kept harder than bee shrimp, nearer Neocaridina hardness with some KH; the preferred figures vary between sources. Shrimp Zone's Neocaridina are raised in remineralised Melbourne tap water, input TDS about 60 ppm, dosed to roughly 160 ppm. Check the parameters for your particular Caridina line first.

Supplements are optional on top of correct GH. Calcium montmorillonite clay is widely used and treated as low risk at small doses, though there is no agreed dosing standard and keepers differ on whether it adds anything once GH is right. Cuttlebone is more debated: it dissolves slowly and unpredictably depending on pH, and soft-water Caridina keepers often avoid it as an uncontrolled hardness source. Leave shed exoskeletons in the tank; shrimp eat them.

If you are seeing repeated moulting deaths, look at swings in GH and TDS, and at how fast you change water, before you blame the food.

How much, and how often

Frequency is where hobby opinion genuinely splits: a tiny amount daily, every second or third day, or five days on and two fasting all produce thriving colonies. What they share is small portions and prompt removal.

Food	Role	Rough frequency	Remove after
Biofilm and algae	Staple	Always available	Not applicable
Prepared shrimp food	Main supplement	Every 2 to 3 days	2 to 3 hours
Blanched vegetables	Variety, fibre	Weekly or less	2 to 3 hours
Leaf litter	Slow-release grazing	A leaf or two monthly	Leave to disintegrate
Powdered biofilm food	Shrimplets, sparse tanks	Sparingly, if at all	Do not re-dose

Use a small glass feeding dish. It keeps food off the substrate, shows what is left, and makes removal a two-second job with a turkey baster.

Feeding through an Australian winter

Shrimp are ectotherms (cold-blooded), so metabolism tracks water temperature. An unheated tank in a Melbourne house in late winter can sit well below the ranges above, often in the high teens, and a colony there eats noticeably less than the same colony at 24 °C.

Through the cold months, halve what you offer and lengthen the gap between feeds. Watch the dish, not the calendar. Cold is the live risk for new arrivals at this time of year, so get them into stable water in the right range and let them settle before feeding at all.

Signs you are overfeeding

• Food still present the next morning.
• Planaria appearing from nowhere. They live on surplus protein and detritus (sunken waste debris), and are a symptom before they are a problem.
• Hydra taking hold. They are predators that increase when surplus food grows the microfauna (tiny water creatures) they eat, and are widely treated as a risk to newly released shrimplets.
• Detritus worms swarming the glass at night.
• Cloudy water a day after feeding, which is a bacterial bloom on dissolved nutrients.
• Any detectable ammonia or nitrite in a tank that had been reading zero.

The fix is the same every time: stop feeding for a week, siphon out the debris, restart smaller. In a mature, well-grazed tank a healthy colony will not starve in that week.

The short version

Plenty of grazing surface. Nothing for the first week, then a crumb every second or third day. Remove what is not eaten within a few hours. Get GH right rather than dosing calcium into food. Feed less when the water is cold. If you are unsure whether to feed today, do not.

More on care, water and settling new shrimp is in the FAQ.